Snapshot replication operations based on incremental block change tracking

ABSTRACT

A system according to certain aspects improves the process of performing snapshot replication operations (e.g., maintaining a mirror copy of primary data at a secondary location by generating snapshots of the primary data). The system can collect and maintain cumulative block-level changes to the primary data after each sub-interval of a plurality of sub-intervals between the snapshots. When a snapshot is generated, any changes to the primary data not reflected in the cumulative block-level changes are identified based on the snapshot and transmitted to the secondary location along with the cumulative block-level changes. By the time the snapshot is generated, some or all of the changes to the primary data associated with the given snapshot have already been included in the cumulative block-level changes, thereby reducing the time and computing resources spent to identify and collect the changes for transmission to the secondary location.

RELATED APPLICATIONS

This disclosure is a continuation of U.S. patent application Ser. No.15/454,917, filed on Mar. 9, 2017 and titled “SNAPSHOT REPLICATIONOPERATIONS BASED ON INCREMENTAL BLOCK CHANGE TRACKING,” which anon-provisional of U.S. Provisional Patent Application No. 62/306,545,filed on Mar. 10, 2016 and titled “IMPROVED SNAPSHOT REPLICATIONOPERATIONS BASED ON INCREMENTAL BLOCK CHANGE TRACKING.” Any and allapplications for which a foreign or domestic priority claim isidentified in the Application Data Sheet of the present application arehereby incorporated by reference under 37 CFR 1.57.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentand/or the patent disclosure as it appears in the United States Patentand Trademark Office patent file and/or records, but otherwise reservesall copyrights whatsoever.

BACKGROUND

Businesses recognize the commercial value of their data and seekreliable, cost-effective ways to protect the information stored on theircomputer networks while minimizing impact on productivity. A companymight back up critical computing systems such as databases, fileservers, web servers, virtual machines, and so on as part of a daily,weekly, or monthly maintenance schedule. The company may similarlyprotect computing systems used by its employees, such as those used byan accounting department, marketing department, engineering department,and so forth. Given the rapidly expanding volume of data undermanagement, companies also continue to seek innovative techniques formanaging data growth, for example by migrating data to lower-coststorage over time, reducing redundant data, pruning lower priority data,etc. Enterprises also increasingly view their stored data as a valuableasset and look for solutions that not only protect and manage, but alsoleverage their data. For instance, data analysis capabilities,information management, improved data presentation and access features,and the like, are in increasing demand.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an exemplary informationmanagement system.

FIG. 1B is a detailed view of a primary storage device, a secondarystorage device, and some examples of primary data and secondary copydata.

FIG. 1C is a block diagram of an exemplary information management systemincluding a storage manager, one or more data agents, and one or moremedia agents.

FIG. 1D is a block diagram illustrating a scalable informationmanagement system.

FIG. 1E illustrates certain secondary copy operations according to anexemplary storage policy.

FIGS. 1F-1H are block diagrams illustrating suitable data structuresthat may be employed by the information management system.

FIG. 2A illustrates a system and technique for synchronizing primarydata to a destination such as a failover site using secondary copy data.

FIG. 2B illustrates an information management system architectureincorporating use of a network file system (NFS) protocol forcommunicating between the primary and secondary storage subsystems.

FIG. 2C is a block diagram of an example of a highly scalable manageddata pool architecture.

FIG. 3 is a block diagram illustrating an exemplary system forfacilitating performing data replication operations across computingplatforms based on network path information, according to anillustrative embodiment.

FIG. 4 is a flow diagram illustrating an example embodiment ofperforming an improved snapshot replication process based on incrementalblock change tracking.

FIG. 5A is an illustrative example of performing a snapshot replicationprocess.

FIG. 5B is an illustrative example of performing an improved snapshotreplication process based on incremental block change tracking.

DETAILED DESCRIPTION

Systems and methods are disclosed for performing improved snapshotreplication operations based on incremental block change tracking. Suchsystems and methods may facilitate maintenance of mirror copies ofprimary data for data restoration and application recovery. By trackingincremental block changes between snapshots, such systems and methodsmay reduce the amount of time and computing resources needed to performsnapshot backups and replications. Examples of such systems and methodsare described in further detail herein, in reference to FIGS. 3-5 and inthe sections entitled “Overview of Improved Snapshot Replication basedon Incremental Block Change Tracking”, “An Exemplary System forImplementing Improved Snapshot Replication Process based on IncrementalBlock Change Tracking”, “An Example Flow Diagram Illustrating ImprovedSnapshot Replication Process”, “An Illustrative Example of ImprovedSnapshot Replication based on Incremental Block Change Tracking”, and“Example Embodiments”. Components and functionality for performingimproved snapshot replication operations based on incremental blockchange tracking may be configured and/or incorporated into informationmanagement systems such as those described herein in FIGS. 1A-1H and2A-2B.

Various embodiments described herein are intimately tied to, enabled by,and would not exist except for, computer technology. For example,performing improved snapshot replication operations based on incrementalblock change tracking described herein in reference to variousembodiments cannot reasonably be performed by humans alone, without thecomputer technology upon which they are implemented.

Information Management System Overview

With the increasing importance of protecting and leveraging data,organizations simply cannot risk losing critical data. Moreover, runawaydata growth and other modern realities make protecting and managing dataincreasingly difficult. There is therefore a need for efficient,powerful, and user-friendly solutions for protecting and managing data.Depending on the size of the organization, there may be many dataproduction sources which are under the purview of tens, hundreds, oreven thousands of individuals. In the past, individuals were sometimesresponsible for managing and protecting their own data, and a patchworkof hardware and software point solutions may have been used in any givenorganization. These solutions were often provided by different vendorsand had limited or no interoperability. Certain embodiments describedherein address these and other shortcomings of prior approaches byimplementing scalable, unified, organization-wide informationmanagement, including data storage management.

FIG. 1A shows one such information management system 100 (or “system100”), which generally includes combinations of hardware and softwareconfigured to protect and manage data and metadata that are generatedand used by computing devices in system 100. System 100 may be referredto in some embodiments as a “storage management system” and theoperations it performs may be referred to as “information managementoperations” or “storage operations” in some circumstances. Theorganization that employs system 100 may be a corporation or otherbusiness entity, non-profit organization, educational institution,household, governmental agency, or the like.

Generally, the systems and associated components described herein may becompatible with and/or provide some or all of the functionality of thesystems and corresponding components described in one or more of thefollowing U.S. patents and patent application publications assigned toCommvault Systems, Inc., each of which is hereby incorporated byreference in its entirety herein:

-   -   U.S. Pat. No. 7,035,880, entitled “Modular Backup and Retrieval        System Used in Conjunction With a Storage Area Network”;    -   U.S. Pat. No. 7,107,298, entitled “System And Method For        Archiving Objects In An Information Store”;    -   U.S. Pat. No. 7,246,207, entitled “System and Method for        Dynamically Performing Storage Operations in a Computer        Network”;    -   U.S. Pat. No. 7,315,923, entitled “System And Method For        Combining Data Streams In Pipelined Storage Operations In A        Storage Network”;    -   U.S. Pat. No. 7,343,453, entitled “Hierarchical Systems and        Methods for Providing a Unified View of Storage Information”;    -   U.S. Pat. No. 7,395,282, entitled “Hierarchical Backup and        Retrieval System”;    -   U.S. Pat. No. 7,529,782, entitled “System and Methods for        Performing a Snapshot and for Restoring Data”;    -   U.S. Pat. No. 7,617,262, entitled “System and Methods for        Monitoring Application Data in a Data Replication System”;    -   U.S. Pat. No. 7,734,669, entitled “Managing Copies Of Data”;    -   U.S. Pat. No. 7,747,579, entitled “Metabase for Facilitating        Data Classification”;    -   U.S. Pat. No. 8,156,086, entitled “Systems And Methods For        Stored Data Verification”;    -   U.S. Pat. No. 8,170,995, entitled “Method and System for Offline        Indexing of Content and Classifying Stored Data”;    -   U.S. Pat. No. 8,230,195, entitled “System And Method For        Performing Auxiliary Storage Operations”;    -   U.S. Pat. No. 8,285,681, entitled “Data Object Store and Server        for a Cloud Storage Environment, Including Data Deduplication        and Data Management Across Multiple Cloud Storage Sites”;    -   U.S. Pat. No. 8,307,177, entitled “Systems And Methods For        Management Of Virtualization Data”;    -   U.S. Pat. No. 8,364,652, entitled “Content-Aligned, Block-Based        Deduplication”;    -   U.S. Pat. No. 8,578,120, entitled “Block-Level Single        Instancing”;    -   U.S. Pat. No. 8,954,446, entitled “Client-Side Repository in a        Networked Deduplicated Storage System “;”;    -   U.S. Pat. No. 9,020,900, entitled “Distributed Deduplicated        Storage System”;    -   U.S. Pat. No. 9,098,495, entitled “Application-Aware and Remote        Single Instance Data Management”;    -   U.S. Pat. No. 9,239,687, entitled “Systems and Methods for        Retaining and Using Data Block Signatures in Data Protection        Operations”;    -   U.S. Pat. Pub. No. 2006/0224846, entitled “System and Method to        Support Single Instance Storage Operations”;    -   U.S. Pat. Pub. No. 2014/0201170, entitled “High Availability        Distributed Deduplicated Storage System”;    -   U.S. patent application Ser. No. 14/721,971, entitled        “Replication Using Deduplicated Secondary Copy Data”;    -   U.S. Patent Application No. 62/265,339 entitled “Live        Synchronization and Management of Virtual Machines across        Computing and Virtualization Platforms and Using Live        Synchronization to Support Disaster Recovery”;    -   U.S. Patent Application No. 62/273,286 entitled “Redundant and        Robust Distributed Deduplication Data Storage System”;    -   U.S. Patent Application No. 62/294,920 entitled “Improved Data        Protection Operations based on Network Path Information”; and    -   U.S. Patent Application No. 62/297,057 entitled “Improved Data        Restoration Operations Based on Network Path Information”.

Information management system 100 can include a variety of computingdevices and computing technologies. For instance, system 100 can includeone or more client computing devices 102 and secondary storage computingdevices 106, as well as storage manager 140 or a host computing devicefor it. Computing devices can include, without limitation, one or more:workstations, personal computers, desktop computers, or other types ofgenerally fixed computing systems such as mainframe computers, servers,and minicomputers. Other computing devices can include mobile orportable computing devices, such as one or more laptops, tabletcomputers, personal data assistants, mobile phones (such assmartphones), and other mobile or portable computing devices such asembedded computers, set top boxes, vehicle-mounted devices, wearablecomputers, etc. Servers can include mail servers, file servers, databaseservers, and web servers. Computing devices may comprise one or moreprocessors (e.g., CPU and/or single-core or multi-core processors), aswell as non-transitory computer-readable memory (e.g., random-accessmemory (RAM)) for storing computer programs to be executed by the one ormore processors. Other computer-readable memory for mass storage of datamay be packaged/configured with the computing device (e.g., an internalhard disk) and/or may be external and accessible by the computing device(e.g., network-attached storage).

In some cases, a computing device includes cloud computing resources,which may be virtual machines. For instance, one or more virtualmachines may be provided to the organization by a third-party cloudservice vendor. In some embodiments, computing devices can include oneor more virtual machine(s) running on a physical host computing device(or “host machine”) operated by the organization. As one example, theorganization may use one virtual machine as a database server andanother virtual machine as a mail server, both virtual machinesoperating on the same host machine.

A virtual machine includes an operating system and associated virtualresources, and is hosted simultaneously with another operating system ona physical host computer (or host machine). A hypervisor (typicallysoftware, and also known in the art as a virtual machine monitor or avirtual machine manager or “VMM”) sits between the virtual machine andthe hardware of the physical host machine. Examples of hypervisors asvirtualization software include ESX Server, by VMware, Inc. of PaloAlto, Calif.; Microsoft Virtual Server and Microsoft Windows ServerHyper-V, both by Microsoft Corporation of Redmond, Wash.; and Sun xVM byOracle America Inc. of Santa Clara, Calif. In some embodiments, thehypervisor may be firmware or hardware or a combination of softwareand/or firmware and/or hardware. The hypervisor provides resources toeach virtual operating system such as a virtual processor, virtualmemory, a virtual network device, and a virtual disk. Each virtualmachine has one or more virtual disks. The hypervisor typically storesthe data of virtual disks in files on the file system of the physicalhost machine, called virtual machine disk files (in VMware lingo) orvirtual hard disk image files (in Microsoft lingo). For example,VMware's ESX Server provides the Virtual Machine File System (VMFS) forthe storage of virtual machine disk files. A virtual machine reads datafrom and writes data to its virtual disk much the way that a physicalmachine reads data from and writes data to a physical disk. Examples oftechniques for implementing information management in a cloud computingenvironment are described in U.S. Pat. No. 8,285,681. Examples oftechniques for implementing information management in a virtualizedcomputing environment are described in U.S. Pat. No. 8,307,177.

Information management system 100 can also include a variety ofelectronic data storage devices, generally used for mass storage ofdata, including, e.g., primary storage devices 104 and secondary storagedevices 108. Storage devices can generally be of any suitable typeincluding, without limitation, disk drives, storage arrays (e.g.,storage-area network (SAN) and/or network-attached storage (NAS)technology), semiconductor memory (e.g., solid state storage devices),network attached storage (NAS) devices, tape libraries or othermagnetic, non-tape storage devices, optical media storage devices,DNA/RNA-based memory technology, combinations of the same, etc. In someembodiments, storage devices can form part of a distributed file system.In some cases, storage devices are provided in a cloud storageenvironment (e.g., a private cloud or one operated by a third-partyvendor), whether for primary data or secondary copies or both.

Depending on context, the term “information management system” can referto generally all of the illustrated hardware and software components inFIG. 1C, or the term may refer to only a subset of the illustratedcomponents. For instance, in some cases, system 100 generally refers toa combination of specialized components used to protect, move, manage,manipulate, analyze, and/or process data and metadata generated byclient computing devices 102. However, system 100 in some cases does notinclude the underlying components that generate and/or store primarydata 112, such as the client computing devices 102 themselves, and theprimary storage devices 104. Likewise secondary storage devices 108(e.g., a third-party provided cloud storage environment) may not be partof system 100. As an example, “information management system” maysometimes refer to one or more of the following components, which willbe described in further detail below: storage manager, data agent, andmedia agent.

Information management system 100 includes one or more client computingdevices 102 having an operating system and at least one application 110executing thereon; and one or more primary storage devices 104 storingprimary data 112. Client computing device(s) 102 and primary storagedevices 104 may generally be referred to in some cases as primarystorage subsystem 117.

Client Computing Devices, Clients, and Subclients

Typically, a variety of sources in an organization produce data to beprotected and managed. As just one illustrative example, in a corporateenvironment such data sources can be employee workstations and companyservers such as a mail server, a web server, a database server, atransaction server, or the like. In system 100, data generation sourcesinclude one or more client computing devices 102. A computing devicethat has a data agent 142 installed and operating on it is generallyreferred to as a “client computing device” 102, and may include any typeof computing device, without limitation. A client computing device 102may be associated with one or more users and/or user accounts.

A “client” is a logical component of information management system 100,which may represent a logical grouping of one or more data agentsinstalled on a client computing device 102. Storage manager 140recognizes a client as a component of system 100, and in someembodiments, may automatically create a client component the first timea data agent 142 is installed on a client computing device 102. Becausedata generated by executable component(s) 110 is tracked by theassociated data agent 142 so that it may be properly protected in system100, a client may be said to generate data and to store the generateddata to primary storage, such as primary storage device 104. However,the terms “client” and “client computing device” as used herein do notimply that a client computing device 102 is necessarily configured inthe client/server sense relative to another computing device such as amail server, or that a client computing device 102 cannot be a server inits own right. As just a few examples, a client computing device 102 canbe and/or include mail servers, file servers, database servers, and webservers.

Each client computing device 102 may have application(s) 110 executingthereon which generate and manipulate the data that is to be protectedfrom loss and managed in system 100. Applications 110 generallyfacilitate the operations of an organization, and can include, withoutlimitation, mail server applications (e.g., Microsoft Exchange Server),file server applications, mail client applications (e.g., MicrosoftExchange Client), database applications or database management systems(e.g., SQL, Oracle, SAP, Lotus Notes Database), word processingapplications (e.g., Microsoft Word), spreadsheet applications, financialapplications, presentation applications, graphics and/or videoapplications, browser applications, mobile applications, entertainmentapplications, and so on. Each application 110 may be accompanied by anapplication-specific data agent 142. A file system, e.g., MicrosoftWindows Explorer, may be considered an application 110 and may beaccompanied by its own data agent 142. Client computing devices 102 canhave at least one operating system (e.g., Microsoft Windows, Mac OS X,iOS, IBM z/OS, Linux, other Unix-based operating systems, etc.)installed thereon, which may support or host one or more file systemsand other applications 110. In some embodiments, a virtual machine thatexecutes on a host client computing device 102 may be considered anapplication 110 and may be accompanied by a specific data agent 142(e.g., virtual server data agent).

Client computing devices 102 and other components in system 100 can beconnected to one another via one or more electronic communicationpathways 114. For example, a first communication pathway 114 maycommunicatively couple client computing device 102 and secondary storagecomputing device 106; a second communication pathway 114 maycommunicatively couple storage manager 140 and client computing device102; and a third communication pathway 114 may communicatively couplestorage manager 140 and secondary storage computing device 106, etc.(see, e.g., FIG. 1A and FIG. 1C). A communication pathway 114 caninclude one or more networks or other connection types including one ormore of the following, without limitation: the Internet, a wide areanetwork (WAN), a local area network (LAN), a Storage Area Network (SAN),a Fibre Channel (FC) connection, a Small Computer System Interface(SCSI) connection, a virtual private network (VPN), a token ring orTCP/IP based network, an intranet network, a point-to-point link, acellular network, a wireless data transmission system, a two-way cablesystem, an interactive kiosk network, a satellite network, a broadbandnetwork, a baseband network, a neural network, a mesh network, an ad hocnetwork, other appropriate computer or telecommunications networks,combinations of the same or the like. Communication pathways 114 in somecases may also include application programming interfaces (APIs)including, e.g., cloud service provider APIs, virtual machine managementAPIs, and hosted service provider APIs. The underlying infrastructure ofcommunication pathways 114 may be wired and/or wireless, analog and/ordigital, or any combination thereof; and the facilities used may beprivate, public, third-party provided, or any combination thereof,without limitation.

A “subclient” is a logical grouping of all or part of a client's primarydata 112. In general a subclient may be defined according to how thesubclient data is to be protected as a unit in system 100. For example,a subclient may be associated with a certain storage policy. A givenclient may thus comprise several subclients, each subclient associatedwith a different storage policy. For example, some files may form afirst subclient that requires compression and deduplication and isassociated with a first storage policy. Other files of the client mayform a second subclient that requires a different retention schedule aswell as encryption, and may be associated with a different, secondstorage policy. As a result, though the primary data may be generated bythe same application 110, and may belong to one given client, portionsof the data may be assigned to different subclients for distincttreatment by the information management system. More detail onsubclients is given in regard to storage policies below.

Primary Data and Exemplary Primary Storage Devices

Primary data 112 is generally production data or other “live” datagenerated by the operating system and/or applications 110 executing onclient computing device 102. Primary data 112 is generally stored onprimary storage device(s) 104 and is organized via a file systemoperating on the client computing device 102. Thus, client computingdevice(s) 102 and corresponding applications 110 may create, access,modify, write, delete, and otherwise use primary data 112. Primary data112 is generally in the native format of the source application 110.According to certain aspects, primary data 112 is an initial or firststored body of data generated by the source application 110. Primarydata 112 in some cases is created substantially directly from datagenerated by the corresponding source application 110.

Primary storage devices 104 storing primary data 112 may be relativelyfast and/or expensive technology (e.g., a disk drive, a hard-diskstorage array, solid state memory, etc.), typically because they mustsupport high-performance live production environments. Primary data 112may be highly changeable and/or may be intended for relatively shortterm retention (e.g., hours, days, or weeks). According to someembodiments, client computing device 102 can access primary data 112stored in primary storage device 104 by making conventional file systemcalls via the operating system. Primary data 112 may include structureddata (e.g., database files), unstructured data (e.g., documents), and/orsemi-structured data. See, e.g., FIG. 1B.

It can be useful in performing certain tasks to organize primary data112 into units of different granularities. In general, primary data 112can include files, directories, file system volumes, data blocks,extents, or any other hierarchies or organizations of data objects. Asused herein, a “data object” can refer to (i) any file that is currentlyaddressable by a file system or that was previously addressable by thefile system (e.g., an archive file), and (ii) a subset of such a file(e.g., a data block, an extent, etc.).

It can also be useful in performing certain functions of system 100 toaccess and modify metadata within primary data 112. Metadata generallyincludes information about data objects and/or characteristicsassociated with the data objects. For simplicity herein, it is to beunderstood that, unless expressly stated otherwise, any reference toprimary data 112 generally also includes its associated metadata, butreferences to metadata generally do not include the primary data.Metadata can include, without limitation, one or more of the following:the data owner (e.g., the client or user that generates the data), thelast modified time (e.g., the time of the most recent modification ofthe data object), a data object name (e.g., a file name), a data objectsize (e.g., a number of bytes of data), information about the content(e.g., an indication as to the existence of a particular search term),user-supplied tags, to/from information for email (e.g., an emailsender, recipient, etc.), creation date, file type (e.g., format orapplication type), last accessed time, application type (e.g., type ofapplication that generated the data object), location/network (e.g., acurrent, past or future location of the data object and network pathwaysto/from the data object), geographic location (e.g., GPS coordinates),frequency of change (e.g., a period in which the data object ismodified), business unit (e.g., a group or department that generates,manages or is otherwise associated with the data object), aginginformation (e.g., a schedule, such as a time period, in which the dataobject is migrated to secondary or long term storage), boot sectors,partition layouts, file location within a file folder directorystructure, user permissions, owners, groups, access control lists(ACLs), system metadata (e.g., registry information), combinations ofthe same or other similar information related to the data object. Inaddition to metadata generated by or related to file systems andoperating systems, some applications 110 and/or other components ofsystem 100 maintain indices of metadata for data objects, e.g., metadataassociated with individual email messages. The use of metadata toperform classification and other functions is described in greaterdetail below.

Each client computing device 102 is generally associated with and/or incommunication with one or more primary storage devices 104 storingcorresponding primary data 112. A client computing device 102 may beconsidered to be associated with or in communication with a primarystorage device 104 if it is capable of one or more of: routing and/orstoring data (e.g., primary data 112) to the particular primary storagedevice 104, coordinating the routing and/or storing of data to theparticular primary storage device 104, retrieving data from theparticular primary storage device 104, coordinating the retrieval ofdata from the particular primary storage device 104, and modifyingand/or deleting data in the particular primary storage device 104. Aclient computing device 102 may be said to access data stored in anassociated storage device 104.

Primary storage device 104 may be dedicated or shared. In some cases,each primary storage device 104 is dedicated to an associated clientcomputing device 102, e.g., a local disk drive. In other cases, one ormore primary storage devices 104 can be shared by multiple clientcomputing devices 102, e.g., via a local network, in a cloud storageimplementation, etc. As one example, primary storage device 104 can be astorage array shared by a group of client computing devices 102, such asEMC Clariion, EMC Symmetrix, EMC Celerra, Dell EqualLogic, IBM XIV,NetApp FAS, HP EVA, and HP 3PAR.

Information management system 100 may also include hosted services (notshown), which may be hosted in some cases by an entity other than theorganization that employs the other components of system 100. Forinstance, the hosted services may be provided by online serviceproviders. Such service providers can provide social networkingservices, hosted email services, or hosted productivity applications orother hosted applications such as software-as-a-service (SaaS),platform-as-a-service (PaaS), application service providers (ASPs),cloud services, or other mechanisms for delivering functionality via anetwork. As it services users, each hosted service may generateadditional data and metadata, which may be managed by system 100, e.g.,as primary data 112. In some cases, the hosted services may be accessedusing one of the applications 110. As an example, a hosted mail servicemay be accessed via browser running on a client computing device 102.

Secondary Copies and Exemplary Secondary Storage Devices

Primary data 112 stored on primary storage devices 104 may becompromised in some cases, such as when an employee deliberately oraccidentally deletes or overwrites primary data 112. Or primary storagedevices 104 can be damaged, lost, or otherwise corrupted. For recoveryand/or regulatory compliance purposes, it is therefore useful togenerate and maintain copies of primary data 112. Accordingly, system100 includes one or more secondary storage computing devices 106 and oneor more secondary storage devices 108 configured to create and store oneor more secondary copies 116 of primary data 112 including itsassociated metadata. The secondary storage computing devices 106 and thesecondary storage devices 108 may be referred to as secondary storagesubsystem 118.

Creation of secondary copies 116 can help in search and analysis effortsand meet other information management goals as well, such as: restoringdata and/or metadata if an original version is lost (e.g., by deletion,corruption, or disaster); allowing point-in-time recovery; complyingwith regulatory data retention and electronic discovery (e-discovery)requirements; reducing utilized storage capacity in the productionsystem and/or in secondary storage; facilitating organization and searchof data; improving user access to data files across multiple computingdevices and/or hosted services; and implementing data retentionpolicies.

A secondary copy 116 can comprise a separate stored copy of data that isderived from one or more earlier-created stored copies (e.g., derivedfrom primary data 112 or from another secondary copy 116). Secondarycopies 116 can include point-in-time data, and may be intended forrelatively long-term retention, before some or all of the data is movedto other storage or discarded. In some cases, a secondary copy 116 maybe in a different storage device than other previously stored copies;and/or may be remote from other previously stored copies. Secondarycopies 116 can be stored in the same storage device as primary data 112.For example, a disk array capable of performing hardware snapshotsstores primary data 112 and creates and stores hardware snapshots of theprimary data 112 as secondary copies 116. Secondary copies 116 may bestored in relatively slow and/or lower cost storage (e.g., magnetictape). A secondary copy 116 may be stored in a backup or archive format,or in some other format different from the native source applicationformat or other format of primary data 112.

Secondary storage computing devices 106 may index secondary copies 116(e.g., using a media agent 144), so that users can browse and restore ata later time. After creation of a secondary copy 116 representative ofcertain primary data 112, a pointer or other location indicia (e.g., astub) may be placed in primary data 112, or be otherwise associated withprimary data 112, to indicate the current location on secondary storagedevice(s) 108 of a particular secondary copy 116.

Since an instance of a data object or metadata in primary data 112 maychange over time as it is modified by application 110 (or hosted serviceor the operating system), system 100 may create and manage multiplesecondary copies 116 of a particular data object or metadata, each copyrepresenting the state of the data object in primary data 112 at aparticular point in time. Moreover, since an instance of a data objectin primary data 112 may eventually be deleted from primary storagedevice 104 and the file system, system 100 may continue to managepoint-in-time representations of that data object, even though theinstance in primary data 112 no longer exists.

For virtual machines, the operating system and other applications 110 ofclient computing device(s) 102 may execute within or under themanagement of virtualization software (e.g., a VMM), and the primarystorage device(s) 104 may comprise a virtual disk created on a physicalstorage device. System 100 may create secondary copies 116 of the filesor other data objects in a virtual disk file and/or secondary copies 116of the entire virtual disk file itself (e.g., of an entire .vmdk file).

Secondary copies 116 may be distinguished from corresponding primarydata 112. First, secondary copies 116 can be stored in a differentformat (e.g., backup, archive, or other non-native format) than primarydata 112. For this or other reasons, secondary copies 116 may not bedirectly useable by applications 110 or client computing device 102(e.g., via standard system calls or otherwise) without modification,processing, or other intervention by system 100 which may be referred toas “restore” operations. Secondary copies 116 may have been processed bydata agent 142 and/or media agent 144 in the course of being created(e.g., compression, deduplication, encryption, integrity markers,indexing, formatting, etc.), and thus secondary copy 116 may representsource primary data 112 without necessarily being exactly identical tothe source.

Second, secondary copies 116 may be stored on a secondary storage device108 that is inaccessible to application 110 running on client computingdevice 102 and/or hosted service. Some secondary copies 116 may be“offline copies,” in that they are not readily available (e.g., notmounted to tape or disk). Offline copies can include copies of data thatsystem 100 can access without human intervention (e.g., tapes within anautomated tape library, but not yet mounted in a drive), and copies thatthe system 100 can access only with some human intervention (e.g., tapeslocated at an offsite storage site).

Using Intermediate Devices for Creating Secondary Copies—SecondaryStorage Computing Devices

Creating secondary copies can be challenging. For instance, hundreds orthousands of client computing devices 102 may be continually generatinglarge volumes of primary data 112 to be protected. Also, there can besignificant overhead involved in the creation of secondary copies 116.Moreover, secondary storage devices 108 may be special-purposecomponents, and devices that write to, read from, or otherwise interactwith secondary storage devices 108, such as secondary storage computingdevices 106 and corresponding media agents 144, may require specializedprogrammed intelligence and/or hardware capability. Client computingdevices 102 may interact directly with a secondary storage device 108 tocreate secondary copies 116; however, in view of the factors describedabove, this approach can negatively impact the ability of clientcomputing device 102 to serve/service application 110 and produceprimary data 112. Further, any given client computing device 102 may notbe optimized for interaction with certain secondary storage devices 108.

Thus, information management system 100 may include one or more softwareand/or hardware components which generally act as intermediaries betweenclient computing devices 102 (that generate primary data 112) andsecondary storage devices 108 (that store secondary copies 116). Inaddition to off-loading certain responsibilities from client computingdevices 102, these intermediate components can provide other benefits.For instance, as discussed further below with respect to FIG. 1D,distributing some of the work involved in creating secondary copies 116can enhance scalability and improve system performance. For instance,using specialized secondary storage computing devices 106 and mediaagents 144 for interfacing with secondary storage devices 108 and/or forperforming certain data processing operations can greatly improve thespeed with which system 100 performs information management operationsand can also improve the capacity of the system to handle large numbersof such operations, while reducing the computational load on theproduction environment of client computing devices 102. The intermediatecomponents can include one or more secondary storage computing devices106 as shown in FIG. 1A and/or one or more media agents 144. Mediaagents are discussed further below (e.g., with respect to FIGS. 1C-1E).

Secondary storage computing device(s) 106 can comprise any of thecomputing devices described above, without limitation. In some cases,secondary storage computing device(s) 106 also include specializedhardware and/or software componentry for interacting with certainsecondary storage device(s) 108 with which they may be speciallyassociated.

To create a secondary copy 116 involving the copying of data fromprimary storage subsystem 117 to secondary storage subsystem 118, clientcomputing device 102 may communicate the primary data 112 to be copied(or a processed version thereof) to the designated secondary storagecomputing device 106, via a communication pathway 114. Secondary storagecomputing device 106 in turn may perform further processing and mayconvey the data (or a processed version thereof) to secondary storagedevice 108. One or more secondary copies 116 may be created fromexisting secondary copies 116, such as in the case of an auxiliary copyoperation, described further below.

Exemplary Primary Data and an Exemplary Secondary Copy

FIG. 1B is a detailed view showing some specific examples of primarydata stored on primary storage device(s) 104 and secondary copy datastored on secondary storage device(s) 108, with other components of thesystem removed for the purposes of illustration. Stored on the primarystorage device(s) 104 are primary data 112 objects including wordprocessing documents 119A-B, spreadsheets 120, presentation documents122, video files 124, image files 126, email mailboxes 128 (andcorresponding email messages 129A-C), html/xml or other types of markuplanguage files 130, databases 132 and corresponding tables or other datastructures 133A-133C). Some or all primary data 112 objects areassociated with corresponding metadata (e.g., “Meta1-11”), which mayinclude file system metadata and/or application-specific metadata.Stored on the secondary storage device(s) 108 are secondary copy 116data objects 134A-C which may include copies of or may otherwiserepresent corresponding primary data 112.

Secondary copy data objects 134A-C can individually represent more thanone primary data object. For example, secondary copy data object 134Arepresents three separate primary data objects 133C, 122, and 129C(represented as 133C′, 122′, and 129C′, respectively, and accompanied bycorresponding metadata Meta11, Meta3, and Meta8, respectively).Moreover, as indicated by the prime mark (′), secondary storagecomputing devices 106 or other components in secondary storage subsystem118 may process the data received from primary storage subsystem 117 andstore a secondary copy including a transformed and/or supplementedrepresentation of a primary data object and/or metadata that isdifferent from the original format, e.g., in a compressed, encrypted,deduplicated, or other modified format. For instance, secondary storagecomputing devices 106 can generate new metadata or other informationbased on said processing, and store the newly generated informationalong with the secondary copies. Secondary copy data object 1346represents primary data objects 120, 1336, and 119A as 120′, 1336′, and119A′, respectively, accompanied by corresponding metadata Meta2,Meta10, and Meta1, respectively. Also, secondary copy data object 134Crepresents primary data objects 133A, 1196, and 129A as 133A′, 1196′,and 129A′, respectively, accompanied by corresponding metadata Meta9,Meta5, and Meta6, respectively.

Exemplary Information Management System Architecture

Information management system 100 can incorporate a variety of differenthardware and software components, which can in turn be organized withrespect to one another in many different configurations, depending onthe embodiment. There are critical design choices involved in specifyingthe functional responsibilities of the components and the role of eachcomponent in system 100. Such design choices can impact performance aswell as the adaptability of system 100 to data growth and other changingcircumstances.

FIG. 1C shows an information management system 100 designed according tothese considerations and which includes: storage manager 140, one ormore data agents 142 executing on client computing device(s) 102 andconfigured to process primary data 112, and one or more media agents 144executing on the one or more secondary storage computing devices 106 forperforming tasks involving the secondary storage devices 108.

Storage Manager

Storage manager 140 is a centralized storage and/or information managerthat is configured to perform certain control functions and also tostore certain critical information about system 100. As noted, thenumber of components in system 100 and the amount of data undermanagement can be large. Managing the components and data is therefore asignificant task, which can grow unpredictably as the number ofcomponents and data scale to meet the needs of the organization. Forthese and other reasons, according to certain embodiments,responsibility for controlling system 100, or at least a significantportion of that responsibility, is allocated to storage manager 140.Storage manager 140 can be adapted independently according to changingcircumstances, without having to replace or re-design the remainder ofthe system. Moreover, a computing device for hosting and/or operating asstorage manager 140 can be selected to best suit the functions andnetworking needs of storage manager 140. These and other advantages aredescribed in further detail below and with respect to FIG. 1D.

Storage manager 140 may be a software module or other application,which, in some embodiments operates in conjunction with one or moreassociated data structures such as a dedicated database (e.g.,management database 146). In some embodiments, storage manager 140 isitself a computing device that performs the functions described herein.The storage manager generally initiates, performs, coordinates and/orcontrols storage and other information management operations performedby the system 100, e.g., to protect and control primary data 112 andsecondary copies 116. In general, storage manager 100 may be said tomanage information management system 100, which includes managingconstituent components such as data agents and media agents, etc.

As shown by the dashed arrowed lines 114 in FIG. 1C, storage manager 140may communicate with and/or control some or all elements of theinformation management system 100, such as data agents 142 and mediaagents 144. In this manner, storage manager 140 may control theoperation of various hardware and software components in system 100. Incertain embodiments, control information originates from storage manager140 and status as well as index reporting is transmitted to storagemanager 140 by the managed components, whereas payload data and metadataare generally communicated between data agents 142 and media agents 144(or otherwise between client computing device(s) 102 and secondarystorage computing device(s) 106), e.g., at the direction of and underthe management of storage manager 140. Control information can generallyinclude parameters and instructions for carrying out informationmanagement operations, such as, without limitation, instructions toperform a task associated with an operation, timing informationspecifying when to initiate a task, data path information specifyingwhat components to communicate with or access in carrying out anoperation, and the like. In other embodiments, some informationmanagement operations are controlled or initiated by other components ofsystem 100 (e.g., by media agents 144 or data agents 142), instead of orin combination with storage manager 140.

According to certain embodiments, storage manager 140 provides one ormore of the following functions:

-   -   communicating with data agents 142 and media agents 144,        including transmitting instructions, messages, and/or queries,        as well as receiving status reports, index information,        messages, and/or queries, and responding to same;    -   initiating execution of information management operations;    -   initiating restore and recovery operations;    -   managing secondary storage devices 108 and inventory/capacity of        the same;    -   allocating secondary storage devices 108 for secondary copy        operations;    -   reporting, searching, and/or classification of data in system        100;    -   monitoring completion of and status reporting related to        information management operations and jobs;    -   tracking movement of data within system 100;    -   tracking age information relating to secondary copies 116,        secondary storage devices 108, comparing the age information        against retention guidelines, and initiating data pruning when        appropriate;    -   tracking logical associations between components in system 100;    -   protecting metadata associated with system 100, e.g., in        management database 146;    -   implementing job management, schedule management, event        management, alert management, reporting, job history        maintenance, user security management, disaster recovery        management, and/or user interfacing for system administrators        and/or end users of system 100;    -   sending, searching, and/or viewing of log files; and    -   implementing operations management functionality.

Storage manager 140 may maintain an associated database 146 (or “storagemanager database 146” or “management database 146”) ofmanagement-related data and information management policies 148.Database 146 can be stored in computer memory accessible by storagemanager 140. Database 146 may include a management index 150 (or “index150”) or other data structure(s) that may store: logical associationsbetween components of the system; user preferences and/or profiles(e.g., preferences regarding encryption, compression, or deduplicationof primary data or secondary copies; preferences regarding thescheduling, type, or other aspects of secondary copy or otheroperations; mappings of particular information management users or useraccounts to certain computing devices or other components, etc.;management tasks; media containerization; or other useful data. Forexample, storage manager 140 may use index 150 to track logicalassociations between media agents 144 and secondary storage devices 108and/or movement of data from primary storage devices 104 to secondarystorage devices 108. For instance, index 150 may store data associatinga client computing device 102 with a particular media agent 144 and/orsecondary storage device 108, as specified in an information managementpolicy 148.

Administrators and others may configure and initiate certain informationmanagement operations on an individual basis. But while this may beacceptable for some recovery operations or other infrequent tasks, it isoften not workable for implementing on-going organization-wide dataprotection and management. Thus, system 100 may utilize informationmanagement policies 148 for specifying and executing informationmanagement operations on an automated basis. Generally, an informationmanagement policy 148 can include a stored data structure or otherinformation source that specifies parameters (e.g., criteria and rules)associated with storage management or other information managementoperations. Storage manager 140 can process an information managementpolicy 148 and/or index 150 and, based on the results, identify aninformation management operation to perform, identify the appropriatecomponents in system 100 to be involved in the operation (e.g., clientcomputing devices 102 and corresponding data agents 142, secondarystorage computing devices 106 and corresponding media agents 144, etc.),establish connections to those components and/or between thosecomponents, and/or instruct and control those components to carry outthe operation. In this manner, system 100 can translate storedinformation into coordinated activity among the various computingdevices in system 100.

Management database 146 may maintain information management policies 148and associated data, although information management policies 148 can bestored in computer memory at any appropriate location outside managementdatabase 146. For instance, an information management policy 148 such asa storage policy may be stored as metadata in a media agent database 152or in a secondary storage device 108 (e.g., as an archive copy) for usein restore or other information management operations, depending on theembodiment. Information management policies 148 are described furtherbelow. According to certain embodiments, management database 146comprises a relational database (e.g., an SQL database) for trackingmetadata, such as metadata associated with secondary copy operations(e.g., what client computing devices 102 and corresponding subclientdata were protected and where the secondary copies are stored and whichmedia agent 144 performed the secondary storage). This and othermetadata may additionally be stored in other locations, such as atsecondary storage computing device 106 or on the secondary storagedevice 108, allowing data recovery without the use of storage manager140 in some cases. Thus, management database 146 may comprise dataneeded to kick off secondary copy operations (e.g., storage policies),status and reporting information about completed jobs (e.g., status onyesterday's backup jobs), and additional information sufficient toenable restore and disaster recovery operations (e.g., media agentassociations, location indexing, content indexing, etc.)

Storage manager 140 may include a jobs agent 156, a user interface 158,and a management agent 154, all of which may be implemented asinterconnected software modules or application programs. These aredescribed further below.

Jobs agent 156 in some embodiments initiates, controls, and/or monitorsthe status of some or all information management operations previouslyperformed, currently being performed, or scheduled to be performed bysystem 100. A job may be a logical grouping of information managementoperations such as generating backup copies of a primary data 112subclient at a certain time every day. Thus, jobs agent 156 may accessinformation management policies 148 (e.g., in management database 146)to determine when and how to initiate/control jobs in system 100.

Storage Manager User Interfaces

User interface 158 may include information processing and displaysoftware, such as a graphical user interface (GUI), an applicationprogram interface (API), and/or other interactive interface(s) throughwhich users and system processes can retrieve information about thestatus of information management operations or issue instructions tosystem 100 and/or its constituent components. Via user interface 158,users may issue instructions to the components in system 100 regardingperformance of secondary copy and recovery operations. For example, auser may modify a schedule concerning the number of pending secondarycopy operations. As another example, a user may employ the GUI to viewthe status of pending secondary copy jobs or to monitor the status ofcertain components in system 100 (e.g., the amount of capacity left in astorage device). Storage manager 140 may track information that permitsit to select, designate, or otherwise identify content indices,deduplication databases, or similar databases or resources or data setswithin its information management cell (or another cell) to be searchedin response to certain queries. Such queries may be entered by the userby interacting with user interface 158.

Various embodiments of information management system 100 may beconfigured and/or designed to generate user interface data useable forrendering the various interactive user interfaces described. The userinterface data may be used by system 100 and/or by another system,device, and/or software program (for example, a browser program), torender the interactive user interfaces. The interactive user interfacesmay be displayed on, for example, electronic displays (including, forexample, touch-enabled displays), consoles, etc., whetherdirect-connected to storage manager 140 or communicatively coupledremotely, e.g., via an internet connection. The present disclosuredescribes various embodiments of interactive and dynamic userinterfaces, some of which may be generated by user interface agent 158,and which are the result of significant technological development. Theuser interfaces described herein may provide improved human-computerinteractions, allowing for significant cognitive and ergonomicefficiencies and advantages over previous systems, including reducedmental workloads, improved decision-making, and the like. User interface158 may operate in a single integrated view or console (not shown). Theconsole may support a reporting capability for generating a variety ofreports, which may be tailored to a particular aspect of informationmanagement.

User interfaces are not exclusive to storage manager 140 and in someembodiments a user may access information locally from a computingdevice component of system 100. For example, some information pertainingto installed data agents 142 and associated data streams may beavailable from client computing device 102. Likewise, some informationpertaining to media agents 144 and associated data streams may beavailable from secondary storage computing device 106.

Storage Manager Management Agent

Management agent 154 can provide storage manager 140 with the ability tocommunicate with other components within information management system100 and/or with other information management cells via network protocolsand application programming interfaces (APIs) including, e.g., HTTP,HTTPS, FTP, REST, virtualization software APIs, cloud service providerAPIs, and hosted service provider APIs.

Management agent 154 also allows multiple information management cellsto communicate with one another. For example, system 100 in some casesmay be one information management cell in a network of multiple cellsadjacent to one another or otherwise logically related, e.g., in a WANor LAN. With this arrangement, the cells may communicate with oneanother through respective management agents 154. Inter-cellcommunication and hierarchy is described in greater detail in e.g., U.S.Pat. No. 7,343,453.

Information Management Cell

An “information management cell” (or “storage operation cell” or “cell”)may generally include a logical and/or physical grouping of acombination of hardware and software components associated withperforming information management operations on electronic data,typically one storage manager 140 and at least one data agent 142(executing on a client computing device 102) and at least one mediaagent 144 (executing on a secondary storage computing device 106). Forinstance, the components shown in FIG. 1C may together form aninformation management cell. Thus, in some configurations, a system 100may be referred to as an information management cell. A given cell maybe identified by the identity of its storage manager 140, which isgenerally responsible for managing the cell.

Multiple cells may be organized hierarchically, so that cells mayinherit properties from hierarchically superior cells or be controlledby other cells in the hierarchy (automatically or otherwise).Alternatively, in some embodiments, cells may inherit or otherwise beassociated with information management policies, preferences,information management operational parameters, or other properties orcharacteristics according to their relative position in a hierarchy ofcells. Cells may also be organized hierarchically according to function,geography, architectural considerations, or other factors useful ordesirable in performing information management operations. For example,a first cell may represent a geographic segment of an enterprise, suchas a Chicago office, and a second cell may represent a differentgeographic segment, such as a New York City office. Other cells mayrepresent departments within a particular office, e.g., human resources,finance, engineering, etc. Where delineated by function, a first cellmay perform one or more first types of information management operations(e.g., one or more first types of secondary copies at a certainfrequency), and a second cell may perform one or more second types ofinformation management operations (e.g., one or more second types ofsecondary copies at a different frequency and under different retentionrules). In general, the hierarchical information is maintained by one ormore storage managers 140 that manage the respective cells (e.g., incorresponding management database(s) 146).

Data Agents

A variety of different applications 110 can operate on a given clientcomputing device 102, including operating systems, file systems,database applications, e-mail applications, and virtual machines, justto name a few. And, as part of the process of creating and restoringsecondary copies 116, the client computing device 102 may be tasked withprocessing and preparing the primary data 112 generated by these variousapplications 110. Moreover, the nature of the processing/preparation candiffer across application types, e.g., due to inherent structural,state, and formatting differences among applications 110 and/or theoperating system of client computing device 102. Each data agent 142 istherefore advantageously configured in some embodiments to assist in theperformance of information management operations based on the type ofdata that is being protected at a client-specific and/orapplication-specific level.

Data agent 142 is a component of information system 100 and is generallydirected by storage manager 140 in creating or restoring secondarycopies 116. Data agent 142 may be a software program (e.g., a set ofexecutable binary files) that executes on the same client computingdevice 102 as the associated application 110 that data agent 142 isconfigured to protect. Data agent 142 is generally responsible formanaging, initiating, or otherwise assisting in the performance ofinformation management operations in reference to its associatedapplication(s) 110 and corresponding primary data 112 which isgenerated/accessed by the particular application(s). For instance, dataagent 142 may take part in copying, archiving, migrating, and/orreplicating of primary data 112 stored in the primary storage device(s)104. Data agent 142 may receive control information from storage manager140, such as commands to transfer copies of data objects and/or metadatato one or more media agents 144. Data agent 142 also may compress,deduplicate, and encrypt primary data 112 before transmitting it tomedia agent 144. Data agent 142 also may receive instructions fromstorage manager 140 to restore (or assist in restoring) a secondary copy116 from secondary storage device 108 to primary storage 104, such thatthe restored data may be accessed by application 110.

Each data agent 142 may be specialized for a particular application 110.For instance, different individual data agents 142 may be designed tohandle Microsoft Exchange data, Lotus Notes data, Microsoft Windows filesystem data, Microsoft Active Directory Objects data, SQL Server data,SharePoint data, Oracle database data, SAP database data, virtualmachines and/or associated data, and other types of data. A file systemdata agent, for example, may handle data files and/or other file systeminformation. If a client computing device 102 has two or more types ofdata 112, a specialized data agent 142 may be used for each data type.For example, to backup, migrate, and/or restore all of the data on aMicrosoft Exchange server, the client computing device 102 may use: aMicrosoft Exchange Mailbox data agent 142 to back up the Exchangemailboxes; a Microsoft Exchange Database data agent 142 to back up theExchange databases; a Microsoft Exchange Public Folder data agent 142 toback up the Exchange Public Folders; and a Microsoft Windows File Systemdata agent 142 to back up the file system of client computing device102. In such embodiments, these specialized data agents 142 may betreated as four separate data agents 142 even though they operate on thesame client computing device 102. Other examples may include archivemanagement data agents such as a migration archiver or a compliancearchiver, Quick Recovery® agents, and continuous data replicationagents. Application-specific data agents 142 can provide improvedperformance as compared to generic agents. For instance, becauseapplication-specific data agents 142 may only handle data for a singlesoftware application, the design of the data agent 142 can bestreamlined. The data agent 142 may therefore execute faster and consumeless persistent storage and/or operating memory than data agentsdesigned to generically accommodate multiple different softwareapplications 110.

Each data agent 142 may be configured to access data and/or metadatastored in the primary storage device(s) 104 associated with data agent142 and its host client computing device 102, and process the dataappropriately. For example, during a secondary copy operation, dataagent 142 may arrange or assemble the data and metadata into one or morefiles having a certain format (e.g., a particular backup or archiveformat) before transferring the file(s) to a media agent 144 or othercomponent. The file(s) may include a list of files or other metadata.

In some embodiments, a data agent 142 may be distributed between clientcomputing device 102 and storage manager 140 (and any other intermediatecomponents) or may be deployed from a remote location or its functionsapproximated by a remote process that performs some or all of thefunctions of data agent 142. In addition, a data agent 142 may performsome functions provided by media agent 144. Other embodiments may employone or more generic data agents 142 that can handle and process datafrom two or more different applications 110, or that can handle andprocess multiple data types, instead of or in addition to usingspecialized data agents 142. For example, one generic data agent 142 maybe used to back up, migrate and restore Microsoft Exchange Mailbox dataand Microsoft Exchange Database data, while another generic data agentmay handle Microsoft Exchange Public Folder data and Microsoft WindowsFile System data.

Media Agents

As noted, off-loading certain responsibilities from client computingdevices 102 to intermediate components such as secondary storagecomputing device(s) 106 and corresponding media agent(s) 144 can providea number of benefits including improved performance of client computingdevice 102, faster information management operations, and enhancedscalability. In one example which will be discussed further below, mediaagent 144 can act as a local cache of recently-copied data and/ormetadata that it stored to secondary storage device(s) 108, thusimproving restore capabilities and performance.

Media agent 144 is a component of information system 100 and isgenerally directed by storage manager 140 in creating or restoringsecondary copies 116. Whereas storage manager 140 generally managesinformation management system 100, media agent 144 provides a portal tosecondary storage devices 108. Media agent 144 may be a software program(e.g., a set of executable binary files) that executes on a secondarystorage computing device 106. Media agent 144 generally manages,coordinates, and facilitates the transmission of data between a clientcomputing device 102 (executing a data agent 142) and secondary storagedevice(s) 108. For instance, other components in the system may interactwith media agent 144 to gain access to data stored on secondary storagedevice(s) 108, (e.g., to browse, read, write, modify, delete, or restoredata). Moreover, media agents 144 can generate and store informationrelating to characteristics of the stored data and/or metadata, or cangenerate and store other types of information that generally providesinsight into the contents of the secondary storage devices 108—generallyreferred to as indexing of the stored secondary copies 116.

Media agents 144 can comprise separate nodes of system 100 (e.g., nodesthat are separate from client computing devices 102, storage manager140, and/or secondary storage devices 108). In general, a node can be alogically and/or physically separate component, and in some cases is acomponent that is individually addressable or otherwise identifiable. Inaddition, each media agent 144 may operate on a dedicated secondarystorage computing device 106, while in other embodiments a plurality ofmedia agents 144 may operate on the same secondary storage computingdevice 106.

A media agent 144 may be associated with a particular secondary storagedevice 108 if that media agent 144 is capable of one or more of: routingand/or storing data to the particular secondary storage device 108;coordinating the routing and/or storing of data to the particularsecondary storage device 108; retrieving data from the particularsecondary storage device 108; coordinating the retrieval of data fromthe particular secondary storage device 108; and modifying and/ordeleting data retrieved from the particular secondary storage device108. Media agent 144 in certain embodiments is physically separate fromthe associated secondary storage device 108. For instance, a media agent144 may operate on a secondary storage computing device 106 in adistinct housing, package, and/or location from the associated secondarystorage device 108. In one example, a media agent 144 operates on afirst server computer and is in communication with a secondary storagedevice(s) 108 operating in a separate rack-mounted RAID-based system.

A media agent 144 associated with a particular secondary storage device108 may instruct secondary storage device 108 to perform an informationmanagement task. For instance, a media agent 144 may instruct a tapelibrary to use a robotic arm or other retrieval means to load or eject acertain storage media, and to subsequently archive, migrate, or retrievedata to or from that media, e.g., for the purpose of restoring data to aclient computing device 102. As another example, a secondary storagedevice 108 may include an array of hard disk drives or solid statedrives organized in a RAID configuration, and media agent 144 mayforward a logical unit number (LUN) and other appropriate information tothe array, which uses the received information to execute the desiredsecondary copy operation. Media agent 144 may communicate with asecondary storage device 108 via a suitable communications link, such asa SCSI or Fiber Channel link.

Each media agent 144 may maintain an associated media agent database152. Media agent database 152 may be stored to a disk or other storagedevice (not shown) that is local to the secondary storage computingdevice 106 on which media agent 144 operates. In other cases, mediaagent database 152 is stored separately from the host secondary storagecomputing device 106. Media agent database 152 can include, among otherthings, a media agent index 153 (see, e.g., FIG. 1C). In some cases,media agent index 153 does not form a part of and is instead separatefrom media agent database 152.

Media agent index 153 (or “index 153”) may be a data structureassociated with the particular media agent 144 that includes informationabout the stored data associated with the particular media agent andwhich may be generated in the course of performing a secondary copyoperation or a restore. Index 153 provides a fast and efficientmechanism for locating/browsing secondary copies 116 or other datastored in secondary storage devices 108 without having to accesssecondary storage device 108 to retrieve the information from there. Forinstance, for each secondary copy 116, index 153 may include metadatasuch as a list of the data objects (e.g., files/subdirectories, databaseobjects, mailbox objects, etc.), a logical path to the secondary copy116 on the corresponding secondary storage device 108, locationinformation (e.g., offsets) indicating where the data objects are storedin the secondary storage device 108, when the data objects were createdor modified, etc. Thus, index 153 includes metadata associated with thesecondary copies 116 that is readily available for use from media agent144. In some embodiments, some or all of the information in index 153may instead or additionally be stored along with secondary copies 116 insecondary storage device 108. In some embodiments, a secondary storagedevice 108 can include sufficient information to enable a “bare metalrestore,” where the operating system and/or software applications of afailed client computing device 102 or another target may beautomatically restored without manually reinstalling individual softwarepackages (including operating systems).

Because index 153 may operate as a cache, it can also be referred to asan “index cache.” In such cases, information stored in index cache 153typically comprises data that reflects certain particulars aboutrelatively recent secondary copy operations. After some triggeringevent, such as after some time elapses or index cache 153 reaches aparticular size, certain portions of index cache 153 may be copied ormigrated to secondary storage device 108, e.g., on a least-recently-usedbasis. This information may be retrieved and uploaded back into indexcache 153 or otherwise restored to media agent 144 to facilitateretrieval of data from the secondary storage device(s) 108. In someembodiments, the cached information may include format orcontainerization information related to archives or other files storedon storage device(s) 108.

In some alternative embodiments media agent 144 generally acts as acoordinator or facilitator of secondary copy operations between clientcomputing devices 102 and secondary storage devices 108, but does notactually write the data to secondary storage device 108. For instance,storage manager 140 (or media agent 144) may instruct a client computingdevice 102 and secondary storage device 108 to communicate with oneanother directly. In such a case, client computing device 102 transmitsdata directly or via one or more intermediary components to secondarystorage device 108 according to the received instructions, and viceversa. Media agent 144 may still receive, process, and/or maintainmetadata related to the secondary copy operations, i.e., may continue tobuild and maintain index 153. In these embodiments, payload data canflow through media agent 144 for the purposes of populating index 153,but not for writing to secondary storage device 108.

Media agent 144 and/or other components such as storage manager 140 mayin some cases incorporate additional functionality, such as dataclassification, content indexing, deduplication, encryption,compression, and the like. Further details regarding these and otherfunctions are described below.

Distributed, Scalable Architecture

As described, certain functions of system 100 can be distributed amongstvarious physical and/or logical components. For instance, one or more ofstorage manager 140, data agents 142, and media agents 144 may operateon computing devices that are physically separate from one another. Thisarchitecture can provide a number of benefits. For instance, hardwareand software design choices for each distributed component can betargeted to suit its particular function. The secondary computingdevices 106 on which media agents 144 operate can be tailored forinteraction with associated secondary storage devices 108 and providefast index cache operation, among other specific tasks. Similarly,client computing device(s) 102 can be selected to effectively serviceapplications 110 in order to efficiently produce and store primary data112.

Moreover, in some cases, one or more of the individual components ofinformation management system 100 can be distributed to multipleseparate computing devices. As one example, for large file systems wherethe amount of data stored in management database 146 is relativelylarge, database 146 may be migrated to or may otherwise reside on aspecialized database server (e.g., an SQL server) separate from a serverthat implements the other functions of storage manager 140. Thisdistributed configuration can provide added protection because database146 can be protected with standard database utilities (e.g., SQL logshipping or database replication) independent from other functions ofstorage manager 140. Database 146 can be efficiently replicated to aremote site for use in the event of a disaster or other data loss at theprimary site. Or database 146 can be replicated to another computingdevice within the same site, such as to a higher performance machine inthe event that a storage manager host computing device can no longerservice the needs of a growing system 100.

The distributed architecture also provides scalability and efficientcomponent utilization. FIG. 1D shows an embodiment of informationmanagement system 100 including a plurality of client computing devices102 and associated data agents 142 as well as a plurality of secondarystorage computing devices 106 and associated media agents 144.Additional components can be added or subtracted based on the evolvingneeds of system 100. For instance, depending on where bottlenecks areidentified, administrators can add additional client computing devices102, secondary storage computing devices 106, and/or secondary storagedevices 108. Moreover, where multiple fungible components are available,load balancing can be implemented to dynamically address identifiedbottlenecks. As an example, storage manager 140 may dynamically selectwhich media agents 144 and/or secondary storage devices 108 to use forstorage operations based on a processing load analysis of media agents144 and/or secondary storage devices 108, respectively.

Where system 100 includes multiple media agents 144 (see, e.g., FIG.1D), a first media agent 144 may provide failover functionality for asecond failed media agent 144. In addition, media agents 144 can bedynamically selected to provide load balancing. Each client computingdevice 102 can communicate with, among other components, any of themedia agents 144, e.g., as directed by storage manager 140. And eachmedia agent 144 may communicate with, among other components, any ofsecondary storage devices 108, e.g., as directed by storage manager 140.Thus, operations can be routed to secondary storage devices 108 in adynamic and highly flexible manner, to provide load balancing, failover,etc. Further examples of scalable systems capable of dynamic storageoperations, load balancing, and failover are provided in U.S. Pat. No.7,246,207.

While distributing functionality amongst multiple computing devices canhave certain advantages, in other contexts it can be beneficial toconsolidate functionality on the same computing device. In alternativeconfigurations, certain components may reside and execute on the samecomputing device. As such, in other embodiments, one or more of thecomponents shown in FIG. 1C may be implemented on the same computingdevice. In one configuration, a storage manager 140, one or more dataagents 142, and/or one or more media agents 144 are all implemented onthe same computing device. In other embodiments, one or more data agents142 and one or more media agents 144 are implemented on the samecomputing device, while storage manager 140 is implemented on a separatecomputing device, etc. without limitation.

Exemplary Types of Information Management Operations

In order to protect and leverage stored data, system 100 can beconfigured to perform a variety of information management operations,which may also be referred to in some cases as storage managementoperations or storage operations. These operations can generally include(i) data movement operations, (ii) processing and data manipulationoperations, and (iii) analysis, reporting, and management operations.

Data Movement Operations, Including Secondary Copy Operations

Data movement operations are generally operations that involve thecopying or migration of data between different locations in system 100.For example, data movement operations can include operations in whichstored data is copied, migrated, or otherwise transferred from one ormore first storage devices to one or more second storage devices, suchas from primary storage device(s) 104 to secondary storage device(s)108, from secondary storage device(s) 108 to different secondary storagedevice(s) 108, from secondary storage devices 108 to primary storagedevices 104, or from primary storage device(s) 104 to different primarystorage device(s) 104, or in some cases within the same primary storagedevice 104 such as within a storage array.

Data movement operations can include by way of example, backupoperations, archive operations, information lifecycle managementoperations such as hierarchical storage management operations,replication operations (e.g., continuous data replication), snapshotoperations, deduplication or single-instancing operations, auxiliarycopy operations, disaster-recovery copy operations, and the like. Aswill be discussed, some of these operations do not necessarily createdistinct copies. Nonetheless, some or all of these operations aregenerally referred to as “secondary copy operations” for simplicity.Data movement also comprises restoring secondary copies.

Backup Operations

A backup operation creates a copy of a version of primary data 112 at aparticular point in time (e.g., one or more files or other data units).Each subsequent backup copy 116 (which is a form of secondary copy 116)may be maintained independently of the first. A backup generallyinvolves maintaining a version of the copied primary data 112 as well asbackup copies 116. Further, a backup copy in some embodiments isgenerally stored in a form that is different from the native format,e.g., a backup format. This contrasts to the version in primary data 112which may instead be stored in a native format of the sourceapplication(s) 110. In various cases, backup copies can be stored in aformat in which the data is compressed, encrypted, deduplicated, and/orotherwise modified from the original native application format. Forexample, a backup copy may be stored in a compressed backup format thatfacilitates efficient long-term storage.

Backup copies 116 can have relatively long retention periods as comparedto primary data 112, which is generally highly changeable. Backup copies116 may be stored on media with slower retrieval times than primarystorage device 104. Some backup copies may have shorter retentionperiods than some other types of secondary copies 116, such as archivecopies (described below). Backups may be stored at an offsite location.

Backup operations can include full backups, differential backups,incremental backups, “synthetic full” backups, and/or creating a“reference copy.” A full backup (or “standard full backup”) in someembodiments is generally a complete image of the data to be protected.However, because full backup copies can consume a relatively largeamount of storage, it can be useful to use a full backup copy as abaseline and only store changes relative to the full backup copy forsubsequent backup copies.

A differential backup operation (or cumulative incremental backupoperation) tracks and stores changes that occurred since the last fullbackup. Differential backups can grow quickly in size, but can restorerelatively efficiently because a restore can be completed in some casesusing only the full backup copy and the latest differential copy.

An incremental backup operation generally tracks and stores changessince the most recent backup copy of any type, which can greatly reducestorage utilization. In some cases, however, restoring can be lengthycompared to full or differential backups because completing a restoreoperation may involve accessing a full backup in addition to multipleincremental backups.

Synthetic full backups generally consolidate data without directlybacking up data from the client computing device. A synthetic fullbackup is created from the most recent full backup (i.e., standard orsynthetic) and subsequent incremental and/or differential backups. Theresulting synthetic full backup is identical to what would have beencreated had the last backup for the subclient been a standard fullbackup. Unlike standard full, incremental, and differential backups,however, a synthetic full backup does not actually transfer data fromprimary storage to the backup media, because it operates as a backupconsolidator. A synthetic full backup extracts the index data of eachparticipating subclient. Using this index data and the previously backedup user data images, it builds new full backup images (e.g., bitmaps),one for each subclient. The new backup images consolidate the index anduser data stored in the related incremental, differential, and previousfull backups into a synthetic backup file that fully represents thesubclient (e.g., via pointers) but does not comprise all its constituentdata.

Any of the above types of backup operations can be at the volume level,file level, or block level. Volume level backup operations generallyinvolve copying of a data volume (e.g., a logical disk or partition) asa whole. In a file-level backup, information management system 100generally tracks changes to individual files and includes copies offiles in the backup copy. For block-level backups, files are broken intoconstituent blocks, and changes are tracked at the block level. Uponrestore, system 100 reassembles the blocks into files in a transparentfashion. Far less data may actually be transferred and copied tosecondary storage devices 108 during a file-level copy than avolume-level copy. Likewise, a block-level copy may transfer less datathan a file-level copy, resulting in faster execution. However,restoring a relatively higher-granularity copy can result in longerrestore times. For instance, when restoring a block-level copy, theprocess of locating constituent blocks can sometimes take longer thanrestoring file-level backups.

A reference copy may comprise copy(ies) of selected objects from backedup data, typically to help organize data by keeping contextualinformation from multiple sources together, and/or help retain specificdata for a longer period of time, such as for legal hold needs. Areference copy generally maintains data integrity, and when the data isrestored, it may be viewed in the same format as the source data. Insome embodiments, a reference copy is based on a specialized client,individual subclient and associated information management policies(e.g., storage policy, retention policy, etc.) that are administeredwithin system 100.

Archive Operations

Because backup operations generally involve maintaining a version of thecopied primary data 112 and also maintaining backup copies in secondarystorage device(s) 108, they can consume significant storage capacity. Toreduce storage consumption, an archive operation according to certainembodiments creates an archive copy 116 by both copying and removingsource data. Or, seen another way, archive operations can involve movingsome or all of the source data to the archive destination. Thus, datasatisfying criteria for removal (e.g., data of a threshold age or size)may be removed from source storage. The source data may be primary data112 or a secondary copy 116, depending on the situation. As with backupcopies, archive copies can be stored in a format in which the data iscompressed, encrypted, deduplicated, and/or otherwise modified from theformat of the original application or source copy. In addition, archivecopies may be retained for relatively long periods of time (e.g., years)and, in some cases are never deleted. Archive copies are generallyretained for longer periods of time than backup copies. In certainembodiments, archive copies may be made and kept for extended periods inorder to meet compliance regulations.

Archiving can also serve the purpose of freeing up space in primarystorage device(s) 104 and easing the demand on computational resourceson client computing device 102. Similarly, when a secondary copy 116 isarchived, the archive copy can therefore serve the purpose of freeing upspace in the source secondary storage device(s) 108. Examples of dataarchiving operations are provided in U.S. Pat. No. 7,107,298.

Snapshot Operations

Snapshot operations can provide a relatively lightweight, efficientmechanism for protecting data. From an end-user viewpoint, a snapshotmay be thought of as an “instant” image of primary data 112 at a givenpoint in time, and may include state and/or status information relativeto an application 110 that creates/manages primary data 112. In oneembodiment, a snapshot may generally capture the directory structure ofan object in primary data 112 such as a file or volume or other data setat a particular moment in time and may also preserve file attributes andcontents. A snapshot in some cases is created relatively quickly, e.g.,substantially instantly, using a minimum amount of file space, but maystill function as a conventional file system backup.

A “hardware snapshot” (or “hardware-based snapshot”) operation can be asnapshot operation where a target storage device (e.g., a primarystorage device 104 or a secondary storage device 108) performs thesnapshot operation in a self-contained fashion, substantiallyindependently, using hardware, firmware and/or software operating on thestorage device itself. For instance, the storage device may performsnapshot operations generally without intervention or oversight from anyof the other components of the system 100, e.g., a storage array maygenerate an “array-created” hardware snapshot and may also manage itsstorage, integrity, versioning, etc. In this manner, hardware snapshotscan off-load other components of system 100 from processing involved increating and managing snapshots.

A “software snapshot” (or “software-based snapshot”) operation, on theother hand, can be a snapshot operation in which one or more othercomponents in information management system 100 (e.g., client computingdevices 102, data agents 142, etc.) implement a software layer thatmanages the snapshot operation via interaction with the target storagedevice. For instance, the component executing the snapshot managementsoftware layer may derive a set of pointers and/or data that representsthe snapshot. The snapshot management software layer may then transmitthe same to the target storage device, along with appropriateinstructions for writing the snapshot. One example of a softwaresnapshot product may be Microsoft Volume Snapshot Service (VSS), whichis part of the Microsoft Windows operating system.

Some types of snapshots do not actually create another physical copy ofall the data as it existed at the particular point in time, but maysimply create pointers that are able to map files and directories tospecific memory locations (e.g., to specific disk blocks) where the dataresides, as it existed at the particular point in time. For example, asnapshot copy may include a set of pointers derived from the file systemor from an application. In some other cases, the snapshot may be createdat the block-level, such that creation of the snapshot occurs withoutawareness of the file system. Each pointer points to a respective storeddata block, so that collectively, the set of pointers reflect thestorage location and state of the data object (e.g., file(s) orvolume(s) or data set(s)) at the particular point in time when thesnapshot copy was created.

An initial snapshot may use only a small amount of disk space needed torecord a mapping or other data structure representing or otherwisetracking the blocks that correspond to the current state of the filesystem. Additional disk space is usually required only when files anddirectories change later on. Furthermore, when files change, typicallyonly the pointers which map to blocks are copied, not the blocksthemselves. For example for “copy-on-write” snapshots, when a blockchanges in primary storage, the block is copied to secondary storage orcached in primary storage before the block is overwritten in primarystorage, and the pointer to that block is changed to reflect the newlocation of that block. The snapshot mapping of file system data mayalso be updated to reflect the changed block(s) at that particular pointin time. In some other cases, a snapshot includes a full physical copyof all or substantially all of the data represented by the snapshot.Further examples of snapshot operations are provided in U.S. Pat. No.7,529,782.

A snapshot copy in many cases can be made quickly and withoutsignificantly impacting primary computing resources because largeamounts of data need not be copied or moved. In some embodiments, asnapshot may exist as a virtual file system, parallel to the actual filesystem. Users in some cases gain read-only access to the record of filesand directories of the snapshot. By electing to restore primary data 112from a snapshot taken at a given point in time, users may also returnthe current file system to the state of the file system that existedwhen the snapshot was taken.

Replication Operations

Another type of secondary copy operation is a replication operation.Some types of secondary copies 116 are used to periodically captureimages of primary data 112 at particular points in time (e.g., backups,archives, and snapshots). However, it can also be useful for recoverypurposes to protect primary data 112 in a more continuous fashion, byreplicating primary data 112 substantially as changes occur. In somecases a replication copy can be a mirror copy, for instance, wherechanges made to primary data 112 are mirrored or substantiallyimmediately copied to another location (e.g., to secondary storagedevice(s) 108). By copying each write operation to the replication copy,two storage systems are kept synchronized or substantially synchronizedso that they are virtually identical at approximately the same time.Where entire disk volumes are mirrored, however, mirroring can requiresignificant amount of storage space and utilizes a large amount ofprocessing resources.

According to some embodiments secondary copy operations are performed onreplicated data that represents a recoverable state, or “known goodstate” of a particular application running on the source system. Forinstance, in certain embodiments, known good replication copies may beviewed as copies of primary data 112. This feature allows the system todirectly access, copy, restore, backup or otherwise manipulate thereplication copies as if the data were the “live” primary data 112. Thiscan reduce access time, storage utilization, and impact on sourceapplications 110, among other benefits. Based on known good stateinformation, system 100 can replicate sections of application data thatrepresent a recoverable state rather than rote copying of blocks ofdata. Examples of replication operations (e.g., continuous datareplication) are provided in U.S. Pat. No. 7,617,262.

Deduplication/Single-Instancing Operations

Deduplication or single-instance storage is useful to reduce the amountof non-primary data. For instance, some or all of the above-describedsecondary copy operations can involve deduplication in some fashion. Newdata is read, broken down into data portions of a selected granularity(e.g., sub-file level blocks, files, etc.), compared with correspondingportions that are already in secondary storage, and only new portionsare stored. Portions that already exist are represented as pointers tothe already-stored data. Thus, a deduplicated secondary copy 116 maycomprise actual data portions copied from primary data 112 and mayfurther comprise pointers to already-stored data, which is generallymore storage-efficient than a full copy.

In order to streamline the comparison process, information managementsystem 100 may calculate and/or store signatures (e.g., hashes orcryptographically unique IDs) corresponding to the individual dataportions in the source data and compare the signatures instead ofcomparing entire data portions. In some cases, only a single instance ofeach data portion is stored, and deduplication operations may thereforebe referred to interchangeably as “single-instancing” operations.Depending on the implementation, however, deduplication operations canstore more than one instance of certain data portions, but nonethelesssignificantly reduce stored-data redundancy. Depending on theembodiment, deduplication portions such as data blocks can be of fixedor variable length. Using variable length blocks can enhancededuplication by responding to changes in the data stream, but caninvolve complex processing. In some cases, system 100 utilizes atechnique for dynamically aligning deduplication blocks based onchanging content in the data stream, as described in U.S. Pat. No.8,364,652.

Information management system 100 can perform deduplication in a varietyof manners at a variety of locations. For instance, in some embodiments,system 100 implements “target-side” deduplication by deduplicating dataat the media agent 144 after being received from data agent 142. In somesuch cases, the media agents 144 are generally configured to manage thededuplication process. For instance, one or more of the media agents 144maintain a corresponding deduplication database that storesdeduplication information (e.g., datablock signatures). Examples of sucha configuration are provided in U.S. Pat. No. 9,020,900. Instead of orin combination with “target-side” deduplication, deduplication can alsobe performed on the “source-side” (or “client-side”), e.g., to reducethe amount of data to be transmitted by data agent 142 to media agent144. Storage manager 140 may communicate with other components withinsystem 100 via network protocols and cloud service provider APIs tofacilitate cloud-based deduplication/single instancing, as exemplifiedin U.S. Pat. No. 8,954,446. Some other deduplication/single instancingtechniques are described in U.S. Pat. Pub. No. 2006/0224846 and U.S.Pat. No. 9,098,495.

Information Lifecycle Management and Hierarchical Storage Management

In some embodiments, files and other data over their lifetime move frommore expensive quick-access storage to less expensive slower-accessstorage. Operations associated with moving data through various tiers ofstorage are sometimes referred to as information lifecycle management(ILM) operations.

One type of ILM operation is a hierarchical storage management (HSM)operation, which generally automatically moves data between classes ofstorage devices, such as from high-cost to low-cost storage devices. Forinstance, an HSM operation may involve movement of data from primarystorage devices 104 to secondary storage devices 108, or between tiersof secondary storage devices 108. With each tier, the storage devicesmay be progressively cheaper, have relatively slower access/restoretimes, etc. For example, movement of data between tiers may occur asdata becomes less important over time. In some embodiments, an HSMoperation is similar to archiving in that creating an HSM copy may(though not always) involve deleting some of the source data, e.g.,according to one or more criteria related to the source data. Forexample, an HSM copy may include primary data 112 or a secondary copy116 that is larger than a given size threshold or older than a given agethreshold. Often, and unlike some types of archive copies, HSM data thatis removed or aged from the source is replaced by a logical referencepointer or stub. The reference pointer or stub can be stored in theprimary storage device 104 or other source storage device, such as asecondary storage device 108 to replace the deleted source data and topoint to or otherwise indicate the new location in (another) secondarystorage device 108.

According to one example, files are generally moved between higher andlower cost storage depending on how often the files are accessed. When auser requests access to HSM data that has been removed or migrated,system 100 uses the stub to locate the data and may make recovery of thedata appear transparent, even though the HSM data may be stored at alocation different from other source data. In this manner, the dataappears to the user (e.g., in file system browsing windows and the like)as if it still resides in the source location (e.g., in a primarystorage device 104). The stub may also include some metadata associatedwith the corresponding data, so that a file system and/or applicationcan provide some information about the data object and/or alimited-functionality version (e.g., a preview) of the data object.

An HSM copy may be stored in a format other than the native applicationformat (e.g., compressed, encrypted, deduplicated, and/or otherwisemodified). In some cases, copies which involve the removal of data fromsource storage and the maintenance of stub or other logical referenceinformation on source storage may be referred to generally as “on-linearchive copies.” On the other hand, copies which involve the removal ofdata from source storage without the maintenance of stub or otherlogical reference information on source storage may be referred to as“off-line archive copies.” Examples of HSM and ILM techniques areprovided in U.S. Pat. No. 7,343,453.

Auxiliary Copy Operations

An auxiliary copy is generally a copy of an existing secondary copy 116.For instance, an initial secondary copy 116 may be derived from primarydata 112 or from data residing in secondary storage subsystem 118,whereas an auxiliary copy is generated from the initial secondary copy116. Auxiliary copies provide additional standby copies of data and mayreside on different secondary storage devices 108 than the initialsecondary copies 116. Thus, auxiliary copies can be used for recoverypurposes if initial secondary copies 116 become unavailable. Exemplaryauxiliary copy techniques are described in further detail in U.S. Pat.No. 8,230,195.

Disaster-Recovery Copy Operations

Information management system 100 may also make and retain disasterrecovery copies, often as secondary, high-availability disk copies.System 100 may create secondary disk copies and store the copies atdisaster recovery locations using auxiliary copy or replicationoperations, such as continuous data replication technologies. Dependingon the particular data protection goals, disaster recovery locations canbe remote from the client computing devices 102 and primary storagedevices 104, remote from some or all of the secondary storage devices108, or both.

Data Manipulation, Including Encryption and Compression

Data manipulation and processing may include encryption and compressionas well as integrity marking and checking, formatting for transmission,formatting for storage, etc. Data may be manipulated “client-side” bydata agent 142 as well as “target-side” by media agent 144 in the courseof creating secondary copy 116.

Encryption Operations

Information management system 100 in some cases is configured to processdata (e.g., files or other data objects, primary data 112, secondarycopies 116, etc.), according to an appropriate encryption algorithm(e.g., Blowfish, Advanced Encryption Standard (AES), Triple DataEncryption Standard (3-DES), etc.) to limit access and provide datasecurity. System 100 in some cases encrypts the data at the clientlevel, such that client computing devices 102 (e.g., data agents 142)encrypt the data prior to transferring it to other components, e.g.,before sending the data to media agents 144 during a secondary copyoperation. In such cases, client computing device 102 may maintain orhave access to an encryption key or passphrase for decrypting the dataupon restore. Encryption can also occur when media agent 144 createsauxiliary copies or archive copies. Encryption may be applied increating a secondary copy 116 of a previously unencrypted secondary copy116, without limitation. In further embodiments, secondary storagedevices 108 can implement built-in, high performance hardware-basedencryption.

Compression Operations

Similar to encryption, system 100 may also or alternatively compressdata in the course of generating a secondary copy 116. Compressionencodes information such that fewer bits are needed to represent theinformation as compared to the original representation. Compressiontechniques are well known in the art. Compression operations may applyone or more data compression algorithms. Compression may be applied increating a secondary copy 116 of a previously uncompressed secondarycopy, e.g., when making archive copies or disaster recovery copies. Theuse of compression may result in metadata that specifies the nature ofthe compression, so that data may be uncompressed on restore ifappropriate.

Data Analysis, Reporting, and Management Operations

Data analysis, reporting, and management operations can differ from datamovement operations in that they do not necessarily involve copying,migration or other transfer of data between different locations in thesystem. For instance, data analysis operations may involve processing(e.g., offline processing) or modification of already stored primarydata 112 and/or secondary copies 116. However, in some embodiments dataanalysis operations are performed in conjunction with data movementoperations. Some data analysis operations include content indexingoperations and classification operations which can be useful inleveraging the data under management to provide enhanced search andother features. Other data analysis operations such as compression andencryption can provide data reduction and security benefits,respectively.

Classification Operations/Content Indexing

In some embodiments, information management system 100 analyzes andindexes characteristics, content, and metadata associated with primarydata 112 (“online content indexing”) and/or secondary copies 116(“off-line content indexing”). Content indexing can identify files orother data objects based on content (e.g., user-defined keywords orphrases, other keywords/phrases that are not defined by a user, etc.),and/or metadata (e.g., email metadata such as “to,”,” “from,” “cc,”“bcc,” attachment name, received time, etc.). Content indexes may besearched and search results may be restored.

Information management system 100 generally organizes and catalogues theresults into a content index, which may be stored within media agentdatabase 152, for example. The content index can also include thestorage locations of or pointer references to indexed data in primarydata 112 or secondary copies 116, as appropriate. The results may alsobe stored elsewhere in system 100 (e.g., in primary storage device 104or in secondary storage device 108). Such content index data providesstorage manager 140 or other components with an efficient mechanism forlocating primary data 112 and/or secondary copies 116 of data objectsthat match particular criteria, thus greatly increasing the search speedcapability of system 100. For instance, search criteria can be specifiedby a user through user interface 158 of storage manager 140. Moreover,when system 100 analyzes data and/or metadata in secondary copies 116 tocreate an “off-line content index,” this operation has no significantimpact on the performance of client computing devices 102 and thus doesnot take a toll on the production environment. Examples of contentindexing techniques are provided in U.S. Pat. No. 8,170,995.

One or more components, such as a content index engine, can beconfigured to scan data and/or associated metadata for classificationpurposes to populate a database (or other data structure) ofinformation, which can be referred to as a “data classificationdatabase” or a “metabase.” Depending on the embodiment, the dataclassification database(s) can be organized in a variety of differentways, including centralization, logical sub-divisions, and/or physicalsub-divisions. For instance, one or more data classification databasesmay be associated with different subsystems or tiers within system 100.As an example, there may be a first metabase associated with primarystorage subsystem 117 and a second metabase associated with secondarystorage subsystem 118. In other cases, there may be one or moremetabases associated with individual components, e.g., client computingdevices 102 and/or media agents 144. In some embodiments, a dataclassification database may reside as one or more data structures withinmanagement database 146, or may be otherwise associated with storagemanager 140 or may reside as a separate component.

In some cases, metabase(s) may be included in separate database(s)and/or on separate storage device(s) from primary data 112 and/orsecondary copies 116, such that operations related to the metabase(s) donot significantly impact performance on other components of informationmanagement system 100. In other cases, metabase(s) may be stored alongwith primary data 112 and/or secondary copies 116. Files or other dataobjects can be associated with identifiers (e.g., tag entries, etc.) tofacilitate searches of stored data objects. Among a number of otherbenefits, the metabase can also allow efficient, automaticidentification of files or other data objects to associate withsecondary copy or other information management operations. For instance,a metabase can dramatically improve the speed with which the informationmanagement system can search through and identify data as compared toother approaches which can involve scanning an entire file system.Examples of metabases and data classification operations are provided inU.S. Pat. Nos. 7,734,669 and 7,747,579.

Management and Reporting Operations

Certain embodiments leverage the integrated ubiquitous nature ofinformation management system 100 to provide useful system-widemanagement and reporting functions. Operations management can generallyinclude monitoring and managing the health and performance of system 100by, without limitation, performing error tracking, generating granularstorage/performance metrics (e.g., job success/failure information,deduplication efficiency, etc.), generating storage modeling and costinginformation, and the like. As an example, storage manager 140 or othercomponent in system 100 may analyze traffic patterns and suggest and/orautomatically route data to minimize congestion. In some embodiments,the system can generate predictions relating to storage operations orstorage operation information. Such predictions, which may be based on atrending analysis, may predict various network operations or resourceusage, such as network traffic levels, storage media use, use ofbandwidth of communication links, use of media agent components, etc.Further examples of traffic analysis, trend analysis, predictiongeneration, and the like are described in U.S. Pat. No. 7,343,453.

In some configurations having a hierarchy of storage operation cells, amaster storage manager 140 may track the status of subordinate cells,such as the status of jobs, system components, system resources, andother items, by communicating with storage managers 140 (or othercomponents) in the respective storage operation cells. Moreover, themaster storage manager 140 may also track status by receiving periodicstatus updates from the storage managers 140 (or other components) inthe respective cells regarding jobs, system components, systemresources, and other items. In some embodiments, a master storagemanager 140 may store status information and other information regardingits associated storage operation cells and other system information inits management database 146 and/or index 150 (or in another location).The master storage manager 140 or other component may also determinewhether certain storage-related or other criteria are satisfied, and mayperform an action or trigger event (e.g., data migration) in response tothe criteria being satisfied, such as where a storage threshold is metfor a particular volume, or where inadequate protection exists forcertain data. For instance, data from one or more storage operationcells is used to dynamically and automatically mitigate recognizedrisks, and/or to advise users of risks or suggest actions to mitigatethese risks. For example, an information management policy may specifycertain requirements (e.g., that a storage device should maintain acertain amount of free space, that secondary copies should occur at aparticular interval, that data should be aged and migrated to otherstorage after a particular period, that data on a secondary volumeshould always have a certain level of availability and be restorablewithin a given time period, that data on a secondary volume may bemirrored or otherwise migrated to a specified number of other volumes,etc.). If a risk condition or other criterion is triggered, the systemmay notify the user of these conditions and may suggest (orautomatically implement) a mitigation action to address the risk. Forexample, the system may indicate that data from a primary copy 112should be migrated to a secondary storage device 108 to free space onprimary storage device 104. Examples of the use of risk factors andother triggering criteria are described in U.S. Pat. No. 7,343,453.

In some embodiments, system 100 may also determine whether a metric orother indication satisfies particular storage criteria sufficient toperform an action. For example, a storage policy or other definitionmight indicate that a storage manager 140 should initiate a particularaction if a storage metric or other indication drops below or otherwisefails to satisfy specified criteria such as a threshold of dataprotection. In some embodiments, risk factors may be quantified intocertain measurable service or risk levels. For example, certainapplications and associated data may be considered to be more importantrelative to other data and services. Financial compliance data, forexample, may be of greater importance than marketing materials, etc.Network administrators may assign priority values or “weights” tocertain data and/or applications corresponding to the relativeimportance. The level of compliance of secondary copy operationsspecified for these applications may also be assigned a certain value.Thus, the health, impact, and overall importance of a service may bedetermined, such as by measuring the compliance value and calculatingthe product of the priority value and the compliance value to determinethe “service level” and comparing it to certain operational thresholdsto determine whether it is acceptable. Further examples of the servicelevel determination are provided in U.S. Pat. No. 7,343,453, which isincorporated by reference herein.

System 100 may additionally calculate data costing and data availabilityassociated with information management operation cells. For instance,data received from a cell may be used in conjunction withhardware-related information and other information about system elementsto determine the cost of storage and/or the availability of particulardata. Exemplary information generated could include how fast aparticular department is using up available storage space, how long datawould take to recover over a particular pathway from a particularsecondary storage device, costs over time, etc. Moreover, in someembodiments, such information may be used to determine or predict theoverall cost associated with the storage of certain information. Thecost associated with hosting a certain application may be based, atleast in part, on the type of media on which the data resides, forexample. Storage devices may be assigned to a particular costcategories, for example. Further examples of costing techniques aredescribed in U.S. Pat. No. 7,343,453.

Any of the above types of information (e.g., information related totrending, predictions, job, cell or component status, risk, servicelevel, costing, etc.) can generally be provided to users via userinterface 158 in a single integrated view or console (not shown). Reporttypes may include: scheduling, event management, media management anddata aging. Available reports may also include backup history, dataaging history, auxiliary copy history, job history, library and drive,media in library, restore history, and storage policy, etc., withoutlimitation. Such reports may be specified and created at a certain pointin time as a system analysis, forecasting, or provisioning tool.Integrated reports may also be generated that illustrate storage andperformance metrics, risks and storage costing information. Moreover,users may create their own reports based on specific needs. Userinterface 158 can include an option to show a “virtual view” of thesystem that graphically depicts the various components in the systemusing appropriate icons. As one example, user interface 158 may providea graphical depiction of primary storage devices 104, secondary storagedevices 108, data agents 142 and/or media agents 144, and theirrelationship to one another in system 100.

In general, the operations management functionality of system 100 canfacilitate planning and decision-making. For example, in someembodiments, a user may view the status of some or all jobs as well asthe status of each component of information management system 100. Usersmay then plan and make decisions based on this data. For instance, auser may view high-level information regarding secondary copy operationsfor system 100, such as job status, component status, resource status(e.g., communication pathways, etc.), and other information. The usermay also drill down or use other means to obtain more detailedinformation regarding a particular component, job, or the like. Furtherexamples are provided in U.S. Pat. No. 7,343,453.

Information management system 100 can also be configured to performsystem-wide e-discovery operations in some embodiments. In general,e-discovery operations provide a unified collection and searchcapability for data in the system, such as data stored in secondarystorage devices 108 (e.g., backups, archives, or other secondary copies116). For example, system 100 may construct and maintain a virtualrepository for data stored in system 100 that is integrated acrosssource applications 110, different storage device types, etc. Accordingto some embodiments, e-discovery utilizes other techniques describedherein, such as data classification and/or content indexing.

Information Management Policies

An information management policy 148 can include a data structure orother information source that specifies a set of parameters (e.g.,criteria and rules) associated with secondary copy and/or otherinformation management operations.

One type of information management policy 148 is a “storage policy.”According to certain embodiments, a storage policy generally comprises adata structure or other information source that defines (or includesinformation sufficient to determine) a set of preferences or othercriteria for performing information management operations. Storagepolicies can include one or more of the following: (1) what data will beassociated with the storage policy, e.g., subclient; (2) a destinationto which the data will be stored; (3) datapath information specifyinghow the data will be communicated to the destination; (4) the type ofsecondary copy operation to be performed; and (5) retention informationspecifying how long the data will be retained at the destination (see,e.g., FIG. 1E). Data associated with a storage policy can be logicallyorganized into subclients, which may represent primary data 112 and/orsecondary copies 116. A subclient may represent static or dynamicassociations of portions of a data volume. Subclients may representmutually exclusive portions. Thus, in certain embodiments, a portion ofdata may be given a label and the association is stored as a staticentity in an index, database or other storage location. Subclients mayalso be used as an effective administrative scheme of organizing dataaccording to data type, department within the enterprise, storagepreferences, or the like. Depending on the configuration, subclients cancorrespond to files, folders, virtual machines, databases, etc. In oneexemplary scenario, an administrator may find it preferable to separatee-mail data from financial data using two different subclients.

A storage policy can define where data is stored by specifying a targetor destination storage device (or group of storage devices). Forinstance, where the secondary storage device 108 includes a group ofdisk libraries, the storage policy may specify a particular disk libraryfor storing the subclients associated with the policy. As anotherexample, where the secondary storage devices 108 include one or moretape libraries, the storage policy may specify a particular tape libraryfor storing the subclients associated with the storage policy, and mayalso specify a drive pool and a tape pool defining a group of tapedrives and a group of tapes, respectively, for use in storing thesubclient data. While information in the storage policy can bestatically assigned in some cases, some or all of the information in thestorage policy can also be dynamically determined based on criteria,which can be set forth in the storage policy. For instance, based onsuch criteria, a particular destination storage device(s) or otherparameter of the storage policy may be determined based oncharacteristics associated with the data involved in a particularsecondary copy operation, device availability (e.g., availability of asecondary storage device 108 or a media agent 144), network status andconditions (e.g., identified bottlenecks), user credentials, and thelike.

Datapath information can also be included in the storage policy. Forinstance, the storage policy may specify network pathways and componentsto utilize when moving the data to the destination storage device(s). Insome embodiments, the storage policy specifies one or more media agents144 for conveying data associated with the storage policy between thesource and destination. A storage policy can also specify the type(s) ofoperations associated with the storage policy, such as a backup,archive, snapshot, auxiliary copy, or the like. Furthermore, retentionparameters can specify how long the resulting secondary copies 116 willbe kept (e.g., a number of days, months, years, etc.), perhaps dependingon organizational needs and/or compliance criteria.

Another type of information management policy 148 is a “schedulingpolicy,” which specifies when and how often to perform operations.Scheduling parameters may specify with what frequency (e.g., hourly,weekly, daily, event-based, etc.) or under what triggering conditionssecondary copy or other information management operations are to takeplace. Scheduling policies in some cases are associated with particularcomponents, such as a subclient, client computing device 102, and thelike.

When adding a new client computing device 102, administrators canmanually configure information management policies 148 and/or othersettings, e.g., via user interface 158. However, this can be an involvedprocess resulting in delays, and it may be desirable to begin dataprotection operations quickly, without awaiting human intervention.Thus, in some embodiments, system 100 automatically applies a defaultconfiguration to client computing device 102. As one example, when oneor more data agent(s) 142 are installed on a client computing device102, the installation script may register the client computing device102 with storage manager 140, which in turn applies the defaultconfiguration to the new client computing device 102. In this manner,data protection operations can begin substantially immediately. Thedefault configuration can include a default storage policy, for example,and can specify any appropriate information sufficient to begin dataprotection operations. This can include a type of data protectionoperation, scheduling information, a target secondary storage device108, data path information (e.g., a particular media agent 144), and thelike.

Another type of information management policy 148 is an “audit policy”(or security policy), which comprises preferences, rules and/or criteriathat protect sensitive data in information management system 100. Forexample, an audit policy may define “sensitive objects” which are filesor data objects that contain particular keywords (e.g., “confidential,”or “privileged”) and/or are associated with particular keywords (e.g.,in metadata) or particular flags (e.g., in metadata identifying adocument or email as personal, confidential, etc.). An audit policy mayfurther specify rules for handling sensitive objects. As an example, anaudit policy may require that a reviewer approve the transfer of anysensitive objects to a cloud storage site, and that if approval isdenied for a particular sensitive object, the sensitive object should betransferred to a local primary storage device 104 instead. To facilitatethis approval, the audit policy may further specify how a secondarystorage computing device 106 or other system component should notify areviewer that a sensitive object is slated for transfer.

Another type of information management policy 148 is a “provisioningpolicy,” which can include preferences, priorities, rules, and/orcriteria that specify how client computing devices 102 (or groupsthereof) may utilize system resources, such as available storage oncloud storage and/or network bandwidth. A provisioning policy specifies,for example, data quotas for particular client computing devices 102(e.g., a number of gigabytes that can be stored monthly, quarterly orannually). Storage manager 140 or other components may enforce theprovisioning policy. For instance, media agents 144 may enforce thepolicy when transferring data to secondary storage devices 108. If aclient computing device 102 exceeds a quota, a budget for the clientcomputing device 102 (or associated department) may be adjustedaccordingly or an alert may trigger.

While the above types of information management policies 148 have beendescribed as separate policies, one or more of these can be generallycombined into a single information management policy 148. For instance,a storage policy may also include or otherwise be associated with one ormore scheduling, audit, or provisioning policies or operationalparameters thereof. Moreover, while storage policies are typicallyassociated with moving and storing data, other policies may beassociated with other types of information management operations. Thefollowing is a non-exhaustive list of items that information managementpolicies 148 may specify:

-   -   schedules or other timing information, e.g., specifying when        and/or how often to perform information management operations;    -   the type of secondary copy 116 and/or copy format (e.g.,        snapshot, backup, archive, HSM, etc.);    -   a location or a class or quality of storage for storing        secondary copies 116 (e.g., one or more particular secondary        storage devices 108);    -   preferences regarding whether and how to encrypt, compress,        deduplicate, or otherwise modify or transform secondary copies        116;    -   which system components and/or network pathways (e.g., preferred        media agents 144) should be used to perform secondary storage        operations;    -   resource allocation among different computing devices or other        system components used in performing information management        operations (e.g., bandwidth allocation, available storage        capacity, etc.);    -   whether and how to synchronize or otherwise distribute files or        other data objects across multiple computing devices or hosted        services; and    -   retention information specifying the length of time primary data        112 and/or secondary copies 116 should be retained, e.g., in a        particular class or tier of storage devices, or within the        system 100.

Information management policies 148 can additionally specify or dependon historical or current criteria that may be used to determine whichrules to apply to a particular data object, system component, orinformation management operation, such as:

-   -   frequency with which primary data 112 or a secondary copy 116 of        a data object or metadata has been or is predicted to be used,        accessed, or modified;    -   time-related factors (e.g., aging information such as time since        the creation or modification of a data object);    -   deduplication information (e.g., hashes, data blocks,        deduplication block size, deduplication efficiency or other        metrics);    -   an estimated or historic usage or cost associated with different        components (e.g., with secondary storage devices 108);    -   the identity of users, applications 110, client computing        devices 102 and/or other computing devices that created,        accessed, modified, or otherwise utilized primary data 112 or        secondary copies 116;    -   a relative sensitivity (e.g., confidentiality, importance) of a        data object, e.g., as determined by its content and/or metadata;    -   the current or historical storage capacity of various storage        devices;    -   the current or historical network capacity of network pathways        connecting various components within the storage operation cell;    -   access control lists or other security information; and    -   the content of a particular data object (e.g., its textual        content) or of metadata associated with the data object.

Exemplary Storage Policy and Secondary Copy Operations

FIG. 1E includes a data flow diagram depicting performance of secondarycopy operations by an embodiment of information management system 100,according to an exemplary storage policy 148A. System 100 includes astorage manager 140, a client computing device 102 having a file systemdata agent 142A and an email data agent 142B operating thereon, aprimary storage device 104, two media agents 144A, 144B, and twosecondary storage devices 108: a disk library 108A and a tape library108B. As shown, primary storage device 104 includes primary data 112A,which is associated with a logical grouping of data associated with afile system (“file system subclient”), and primary data 112B, which is alogical grouping of data associated with email (“email subclient”). Thetechniques described with respect to FIG. 1E can be utilized inconjunction with data that is otherwise organized as well.

As indicated by the dashed box, the second media agent 144B and tapelibrary 108B are “off-site,” and may be remotely located from the othercomponents in system 100 (e.g., in a different city, office building,etc.). Indeed, “off-site” may refer to a magnetic tape located in remotestorage, which must be manually retrieved and loaded into a tape driveto be read. In this manner, information stored on the tape library 108Bmay provide protection in the event of a disaster or other failure atthe main site(s) where data is stored.

The file system subclient 112A in certain embodiments generallycomprises information generated by the file system and/or operatingsystem of client computing device 102, and can include, for example,file system data (e.g., regular files, file tables, mount points, etc.),operating system data (e.g., registries, event logs, etc.), and thelike. The e-mail subclient 112B can include data generated by an e-mailapplication operating on client computing device 102, e.g., mailboxinformation, folder information, emails, attachments, associateddatabase information, and the like. As described above, the subclientscan be logical containers, and the data included in the correspondingprimary data 112A and 112B may or may not be stored contiguously.

The exemplary storage policy 148A includes backup copy preferences (orrule set) 160, disaster recovery copy preferences or rule set 162, andcompliance copy preferences or rule set 164. Backup copy rule set 160specifies that it is associated with file system subclient 166 and emailsubclient 168. Each of subclients 166 and 168 are associated with theparticular client computing device 102. Backup copy rule set 160 furtherspecifies that the backup operation will be written to disk library 108Aand designates a particular media agent 144A to convey the data to disklibrary 108A. Finally, backup copy rule set 160 specifies that backupcopies created according to rule set 160 are scheduled to be generatedhourly and are to be retained for 30 days. In some other embodiments,scheduling information is not included in storage policy 148A and isinstead specified by a separate scheduling policy.

Disaster recovery copy rule set 162 is associated with the same twosubclients 166 and 168. However, disaster recovery copy rule set 162 isassociated with tape library 108B, unlike backup copy rule set 160.Moreover, disaster recovery copy rule set 162 specifies that a differentmedia agent, namely 144B, will convey data to tape library 108B.Disaster recovery copies created according to rule set 162 will beretained for 60 days and will be generated daily. Disaster recoverycopies generated according to disaster recovery copy rule set 162 canprovide protection in the event of a disaster or other catastrophic dataloss that would affect the backup copy 116A maintained on disk library108A.

Compliance copy rule set 164 is only associated with the email subclient168, and not the file system subclient 166. Compliance copies generatedaccording to compliance copy rule set 164 will therefore not includeprimary data 112A from the file system subclient 166. For instance, theorganization may be under an obligation to store and maintain copies ofemail data for a particular period of time (e.g., 10 years) to complywith state or federal regulations, while similar regulations do notapply to file system data. Compliance copy rule set 164 is associatedwith the same tape library 108B and media agent 144B as disasterrecovery copy rule set 162, although a different storage device or mediaagent could be used in other embodiments. Finally, compliance copy ruleset 164 specifies that copies generated under compliance copy rule set164 will be retained for 10 years and will be generated quarterly.

Secondary Copy Jobs

A logical grouping of secondary copy operations governed by a rule setand being initiated at a point in time may be referred to as a“secondary copy job” and sometimes may be called a “backup job,” eventhough it is not necessarily limited to creating backup copies.Secondary copy jobs may be initiated on demand as well. Steps 1-9 belowillustrate three secondary copy jobs based on storage policy 148A.

At step 1, storage manager 140 initiates a backup job according to thebackup copy rule set 160, which logically comprises all the secondarycopy operations necessary to effectuate rules 160 in storage policy 148Aevery hour, including steps 1-4 occurring hourly. For instance, ascheduling service running on storage manager 140 accesses backup copyrule set 160 or a separate scheduling policy associated with clientcomputing device 102 and initiates a backup job on an hourly basis.Thus, at the scheduled time, storage manager 140 sends instructions toclient computing device 102 (i.e., to both data agent 142A and dataagent 142B) to begin the backup job.

At step 2, file system data agent 142A and email data agent 142Boperating on client computing device 102 respond to the instructionsreceived from storage manager 140 by accessing and processing therespective subclient primary data 112A and 112B involved in the backupcopy operation, which can be found in primary storage device 104.Because the secondary copy operation is a backup copy operation, thedata agent(s) 142A, 142B may format the data into a backup format orotherwise process the data suitable for a backup copy.

At step 3, client computing device 102 (e.g., using file system dataagent 142A) communicates the processed data to the first media agent144A according to backup copy rule set 160, as directed by storagemanager 140. Storage manager 140 may further keep a record in managementdatabase 146 of the association between media agent 144A and one or moreof: client computing device 102, file system data agent 142A, and/orbackup copy 116A.

The target media agent 144A receives the data-agent-processed data fromclient computing device 102, and at step 4 generates and conveys backupcopy 116A to disk library 108A to be stored as backup copy 116A, againat the direction of storage manager 140 and according to backup copyrule set 160. Media agent 144A can also update its index 153 to includedata and/or metadata related to backup copy 116A, such as informationindicating where the backup copy 116A resides on disk library 108A, dataand metadata for cache retrieval, etc. Storage manager 140 may similarlyupdate its index 150 to include information relating to the secondarycopy operation, such as information relating to the type of operation, aphysical location associated with one or more copies created by theoperation, the time the operation was performed, status informationrelating to the operation, the components involved in the operation, andthe like. In some cases, storage manager 140 may update its index 150 toinclude some or all of the information stored in index 153 of mediaagent 144A. At this point, the backup job may be considered complete.After the 30-day retention period expires, storage manager 140 instructsmedia agent 144A to delete backup copy 116A from disk library 108A andindexes 150 and/or 153 are updated accordingly.

At step 5, storage manager 140 initiates another backup job according tothe disaster recovery rule set 162. Illustratively this includes steps5-7 occurring daily for creating disaster recovery copy 116B. Disasterrecovery copy 116B will be based on backup copy 116A and not on primarydata 112A and 112B.

At step 6, illustratively based on instructions received from storagemanager 140 at step 5, the specified media agent 144B retrieves the mostrecent backup copy 116A from disk library 108A.

At step 7, again at the direction of storage manager 140 and asspecified in disaster recovery copy rule set 162, media agent 144B usesthe retrieved data to create a disaster recovery copy 116B and store itto tape library 108B. In some cases, disaster recovery copy 116B is adirect, mirror copy of backup copy 116A, and remains in the backupformat. In other embodiments, disaster recovery copy 116B may begenerated in some other manner, such as by using primary data 112A, 112Bfrom primary storage device 104 as source data. The disaster recoverycopy operation is initiated once a day and disaster recovery copies 116Bare deleted after 60 days; indexes 153 and/or 150 are updatedaccordingly when/after each information management operation is executedand/or completed. The present backup job may be considered to becomplete.

At step 8, storage manager 140 initiates another backup job according tocompliance rule set 164, which includes steps 8-9 occurring quarterlyfor creating compliance copy 116C. For instance, storage manager 140instructs media agent 144B to create compliance copy 116C on tapelibrary 108B, as specified in the compliance copy rule set 164.

At step 9 in the example, compliance copy 116C is generated usingdisaster recovery copy 116B as the source. In other embodiments,compliance copy 116C is instead generated using primary data 112Bcorresponding to the email subclient or using backup copy 116A from disklibrary 108A as source data. As specified in the illustrated example,compliance copies 116C are created quarterly, and are deleted after tenyears, and indexes 153 and/or 150 are kept up-to-date accordingly.

Exemplary Applications of Storage Policies—Information GovernancePolicies and Classification

Storage manager 140 may permit a user to specify aspects of storagepolicy 148A. For example, the storage policy can be modified to includeinformation governance policies to define how data should be managed inorder to comply with a certain regulation or business objective. Thevarious policies may be stored, for example, in management database 146.An information governance policy may align with one or more compliancetasks that are imposed by regulations or business requirements. Examplesof information governance policies might include a Sarbanes-Oxleypolicy, a HIPAA policy, an electronic discovery (e-discovery) policy,and so on.

Information governance policies allow administrators to obtain differentperspectives on an organization's online and offline data, without theneed for a dedicated data silo created solely for each differentviewpoint. As described previously, the data storage systems hereinbuild an index that reflects the contents of a distributed data set thatspans numerous clients and storage devices, including both primary dataand secondary copies, and online and offline copies. An organization mayapply multiple information governance policies in a top-down manner overthat unified data set and indexing schema in order to view andmanipulate the data set through different lenses, each of which isadapted to a particular compliance or business goal. Thus, for example,by applying an e-discovery policy and a Sarbanes-Oxley policy, twodifferent groups of users in an organization can conduct two verydifferent analyses of the same underlying physical set of data/copies,which may be distributed throughout the information management system.

An information governance policy may comprise a classification policy,which defines a taxonomy of classification terms or tags relevant to acompliance task and/or business objective. A classification policy mayalso associate a defined tag with a classification rule. Aclassification rule defines a particular combination of criteria, suchas users who have created, accessed or modified a document or dataobject; file or application types; content or metadata keywords; clientsor storage locations; dates of data creation and/or access; reviewstatus or other status within a workflow (e.g., reviewed orun-reviewed); modification times or types of modifications; and/or anyother data attributes in any combination, without limitation. Aclassification rule may also be defined using other classification tagsin the taxonomy. The various criteria used to define a classificationrule may be combined in any suitable fashion, for example, via Booleanoperators, to define a complex classification rule. As an example, ane-discovery classification policy might define a classification tag“privileged” that is associated with documents or data objects that (1)were created or modified by legal department staff, or (2) were sent toor received from outside counsel via email, or (3) contain one of thefollowing keywords: “privileged” or “attorney” or “counsel,” or otherlike terms. Accordingly, all these documents or data objects will beclassified as “privileged.”

One specific type of classification tag, which may be added to an indexat the time of indexing, is an “entity tag.” An entity tag may be, forexample, any content that matches a defined data mask format. Examplesof entity tags might include, e.g., social security numbers (e.g., anynumerical content matching the formatting mask XXX-XX-XXXX), credit cardnumbers (e.g., content having a 13-16 digit string of numbers), SKUnumbers, product numbers, etc. A user may define a classification policyby indicating criteria, parameters or descriptors of the policy via agraphical user interface, such as a form or page with fields to befilled in, pull-down menus or entries allowing one or more of severaloptions to be selected, buttons, sliders, hypertext links or other knownuser interface tools for receiving user input, etc. For example, a usermay define certain entity tags, such as a particular product number orproject ID code that is relevant in the organization. In someimplementations, the classification policy can be implemented usingcloud-based techniques. For example, the storage devices may be cloudstorage devices, and the storage manager 140 may execute cloud serviceprovider API over a network to classify data stored on cloud storagedevices.

Restore Operations from Secondary Copies

While not shown in FIG. 1E, at some later point in time, a restoreoperation can be initiated involving one or more of secondary copies116A, 1166, 116C. A restore operation logically takes a selectedsecondary copy 116, reverses the effects of the secondary copy operationthat created it, and stores the restored data to primary storage where aclient computing device 102 may properly access it as primary data. Amedia agent 144 and an appropriate data agent 142 (e.g., executing onthe client computing device 102) perform the tasks needed to complete arestore operation. For example, data that was encrypted, compressed,and/or deduplicated in the creation of secondary copy 116 will becorrespondingly rehydrated (reversing deduplication), uncompressed, andunencrypted into a format appropriate to primary data. In general,restored data should be indistinguishable from other primary data 112.Preferably, the restored data has fully regained the native format thatmay make it immediately usable by application 110.

As one example, a user may manually initiate a restore of backup copy116A, e.g., by interacting with user interface 158 of storage manager140 or with a web-based console with access to system 100. Storagemanager 140 may accesses data in its index 150 and/or managementdatabase 146 (and/or the respective storage policy 148A) associated withthe selected backup copy 116A to identify the appropriate media agent144A and/or secondary storage device 108A where the secondary copyresides. The user may be presented with a representation (e.g., stub,thumbnail, listing, etc.) and metadata about the selected secondarycopy, in order to determine whether this is the appropriate copy to berestored, e.g., date that the original primary data was created. Storagemanager 140 will then instruct media agent 144A and an appropriate dataagent 142 to restore secondary copy 116A to primary storage device 104.A media agent may be selected for use in the restore operation based ona load balancing algorithm, an availability based algorithm, or othercriteria. The selected media agent, e.g., 144A, retrieves secondary copy116A from disk library 108A. For instance, media agent 144A may accessits index 153 to identify a location of backup copy 116A on disk library108A, or may access location information residing on disk library 108Aitself.

In some cases when backup copy 116A was recently created or accessed,caching may speed up the restore operation. In such a case, media agent144A accesses a cached version of backup copy 116A residing in index153, without having to access disk library 108A for some or all of thedata. Once it has retrieved backup copy 116A, the media agent 144Acommunicates the data to the requesting client computing device 102.Upon receipt, file system data agent 142A and email data agent 142B mayunpackage (e.g., restore from a backup format to the native applicationformat) the data in backup copy 116A and restore the unpackaged data toprimary storage device 104. In general, secondary copies 116 may berestored to the same volume or folder in primary storage device 104 fromwhich the secondary copy was derived; to another storage location orclient computing device 102; to shared storage. In some cases the datamay be restored so that it may be used by an application 110 of adifferent version/vintage from the application that created the originalprimary data 112.

Exemplary Secondary Copy Formatting

The formatting and structure of secondary copies 116 can vary dependingon the embodiment. In some cases, secondary copies 116 are formatted asa series of logical data units or “chunks” (e.g., 512 MB, 1 GB, 2 GB, 4GB, or 8 GB chunks). This can facilitate efficient communication andwriting to secondary storage devices 108, e.g., according to resourceavailability. For example, a single secondary copy 116 may be written ona chunk-by-chunk basis to one or more secondary storage devices 108. Insome cases, users can select different chunk sizes, e.g., to improvethroughput to tape storage devices. Generally, each chunk can include aheader and a payload. The payload can include files (or other dataunits) or subsets thereof included in the chunk, whereas the chunkheader generally includes metadata relating to the chunk, some or all ofwhich may be derived from the payload. For example, during a secondarycopy operation, media agent 144, storage manager 140, or other componentmay divide files into chunks and generate headers for each chunk byprocessing the files. The headers can include a variety of informationsuch as file identifier(s), volume(s), offset(s), or other informationassociated with the payload data items, a chunk sequence number, etc.Importantly, in addition to being stored with secondary copy 116 onsecondary storage device 108, the chunk headers can also be stored toindex 153 of the associated media agent(s) 144 and/or to index 150associated with storage manager 140. This can be useful in some casesfor providing faster processing of secondary copies 116 during browsing,restores, or other operations. In some cases, once a chunk issuccessfully transferred to a secondary storage device 108, thesecondary storage device 108 returns an indication of receipt, e.g., tomedia agent 144 and/or storage manager 140, which may update theirrespective indexes 153, 150 accordingly. During restore, chunks may beprocessed (e.g., by media agent 144) according to the information in thechunk header to reassemble the files.

Data can also be communicated within system 100 in data channels thatconnect client computing devices 102 to secondary storage devices 108.These data channels can be referred to as “data streams,” and multipledata streams can be employed to parallelize an information managementoperation, improving data transfer rate, among other advantages. Exampledata formatting techniques including techniques involving datastreaming, chunking, and the use of other data structures in creatingsecondary copies are described in U.S. Pat. Nos. 7,315,923 8,156,086,and 8,578,120.

FIGS. 1F and 1G are diagrams of example data streams 170 and 171,respectively, which may be employed for performing informationmanagement operations. Referring to FIG. 1F, data agent 142 forms datastream 170 from source data associated with a client computing device102 (e.g., primary data 112). Data stream 170 is composed of multiplepairs of stream header 172 and stream data (or stream payload) 174. Datastreams 170 and 171 shown in the illustrated example are for asingle-instanced storage operation, and a stream payload 174 thereforemay include both single-instance (SI) data and/or non-SI data. A streamheader 172 includes metadata about the stream payload 174. This metadatamay include, for example, a length of the stream payload 174, anindication of whether the stream payload 174 is encrypted, an indicationof whether the stream payload 174 is compressed, an archive fileidentifier (ID), an indication of whether the stream payload 174 issingle instanceable, and an indication of whether the stream payload 174is a start of a block of data.

Referring to FIG. 1G, data stream 171 has the stream header 172 andstream payload 174 aligned into multiple data blocks. In this example,the data blocks are of size 64 KB. The first two stream header 172 andstream payload 174 pairs comprise a first data block of size 64 KB. Thefirst stream header 172 indicates that the length of the succeedingstream payload 174 is 63 KB and that it is the start of a data block.The next stream header 172 indicates that the succeeding stream payload174 has a length of 1 KB and that it is not the start of a new datablock. Immediately following stream payload 174 is a pair comprising anidentifier header 176 and identifier data 178. The identifier header 176includes an indication that the succeeding identifier data 178 includesthe identifier for the immediately previous data block. The identifierdata 178 includes the identifier that the data agent 142 generated forthe data block. The data stream 171 also includes other stream header172 and stream payload 174 pairs, which may be for SI data and/or non-SIdata.

FIG. 1H is a diagram illustrating data structures 180 that may be usedto store blocks of SI data and non-SI data on a storage device (e.g.,secondary storage device 108). According to certain embodiments, datastructures 180 do not form part of a native file system of the storagedevice. Data structures 180 include one or more volume folders 182, oneor more chunk folders 184/185 within the volume folder 182, and multiplefiles within chunk folder 184. Each chunk folder 184/185 includes ametadata file 186/187, a metadata index file 188/189, one or morecontainer files 190/191/193, and a container index file 192/194.Metadata file 186/187 stores non-SI data blocks as well as links to SIdata blocks stored in container files. Metadata index file 188/189stores an index to the data in the metadata file 186/187. Containerfiles 190/191/193 store SI data blocks. Container index file 192/194stores an index to container files 190/191/193. Among other things,container index file 192/194 stores an indication of whether acorresponding block in a container file 190/191/193 is referred to by alink in a metadata file 186/187. For example, data block B2 in thecontainer file 190 is referred to by a link in metadata file 187 inchunk folder 185. Accordingly, the corresponding index entry incontainer index file 192 indicates that data block B2 in container file190 is referred to. As another example, data block B1 in container file191 is referred to by a link in metadata file 187, and so thecorresponding index entry in container index file 192 indicates thatthis data block is referred to.

As an example, data structures 180 illustrated in FIG. 1H may have beencreated as a result of separate secondary copy operations involving twoclient computing devices 102. For example, a first secondary copyoperation on a first client computing device 102 could result in thecreation of the first chunk folder 184, and a second secondary copyoperation on a second client computing device 102 could result in thecreation of the second chunk folder 185. Container files 190/191 in thefirst chunk folder 184 would contain the blocks of SI data of the firstclient computing device 102. If the two client computing devices 102have substantially similar data, the second secondary copy operation onthe data of the second client computing device 102 would result in mediaagent 144 storing primarily links to the data blocks of the first clientcomputing device 102 that are already stored in the container files190/191. Accordingly, while a first secondary copy operation may resultin storing nearly all of the data subject to the operation, subsequentsecondary storage operations involving similar data may result insubstantial data storage space savings, because links to already storeddata blocks can be stored instead of additional instances of datablocks.

If the operating system of the secondary storage computing device 106 onwhich media agent 144 operates supports sparse files, then when mediaagent 144 creates container files 190/191/193, it can create them assparse files. A sparse file is a type of file that may include emptyspace (e.g., a sparse file may have real data within it, such as at thebeginning of the file and/or at the end of the file, but may also haveempty space in it that is not storing actual data, such as a contiguousrange of bytes all having a value of zero). Having container files190/191/193 be sparse files allows media agent 144 to free up space incontainer files 190/191/193 when blocks of data in container files190/191/193 no longer need to be stored on the storage devices. In someexamples, media agent 144 creates a new container file 190/191/193 whena container file 190/191/193 either includes 100 blocks of data or whenthe size of the container file 190 exceeds 50 MB. In other examples,media agent 144 creates a new container file 190/191/193 when acontainer file 190/191/193 satisfies other criteria (e.g., it containsfrom approximately 100 to approximately 1000 blocks or when its sizeexceeds approximately 50 MB to 1 GB). In some cases, a file on which asecondary copy operation is performed may comprise a large number ofdata blocks. For example, a 100 MB file may comprise 400 data blocks ofsize 256 KB. If such a file is to be stored, its data blocks may spanmore than one container file, or even more than one chunk folder. Asanother example, a database file of 20 GB may comprise over 40,000 datablocks of size 512 KB. If such a database file is to be stored, its datablocks will likely span multiple container files, multiple chunkfolders, and potentially multiple volume folders. Restoring such filesmay require accessing multiple container files, chunk folders, and/orvolume folders to obtain the requisite data blocks.Using Backup Data for Replication and Disaster Recovery (“LiveSynchronization”)

There is an increased demand to offload resource intensive informationmanagement tasks (e.g., data replication tasks) away from productiondevices (e.g., physical or virtual client computing devices) in order tomaximize production efficiency. At the same time, enterprises expectaccess to readily available, up-to-date recovery copies in the event offailure, with little or no production downtime.

FIG. 2A illustrates a system 200 configured to address these and otherissues by using backup or other secondary copy data to synchronize asource subsystem 201 (e.g., a production site) with a destinationsubsystem 203 (e.g., a failover site). Such a technique can be referredto as “live synchronization” and/or “live synchronization replication.”In the illustrated embodiment, the source client computing devices 202 ainclude one or more virtual machines (or “VMs”) executing on one or morecorresponding VM host computers 205 a. The destination site 203 may beat a location that is remote from the production site 201, for example,but may be located in the same data center, without limitation. One ormore of the production site 201 and destination site 203 may reside atdata centers at known geographic locations, or alternatively may operate“in the cloud.”

The synchronization can be achieved by generally applying an ongoingstream of incremental backups from the source subsystem 201 to thedestination subsystem 203, such as according to what can be referred toas an “incremental forever” approach. FIG. 2A illustrates an embodimentof a data flow which may be orchestrated at the direction of one or morestorage managers (not shown). At step 1 the source data agent(s) 242 aand source media agent(s) 244 a work together to write backup or othersecondary copies of the primary data generated by the source clientcomputing devices 202 a into the source secondary storage device(s) 208a. At step 2 the backup data is retrieved by the source media agent(s)244 a, and at step 3 the source media agent(s) 244 a communicate thebackup data across a network to the destination media agent(s) 244 b inthe destination subsystem 203.

As shown, the data can be copied in an incremental fashion, such thatonly changed blocks are transmitted. An example of live synchronizationof virtual machines is found in U.S. Patent Application No. 62/265,339entitled “Live Synchronization and Management of Virtual Machines acrossComputing and Virtualization Platforms and Using Live Synchronization toSupport Disaster Recovery,” which is incorporated by reference in itsentirety herein. Moreover, a deduplicated copy can be employed. Forinstance, the system can utilize one or more of the deduplicated copytechniques described in U.S. Pat. No. 9,239,687, entitled “Systems andMethods for Retaining and Using Data Block Signatures in Data ProtectionOperations,” which is incorporated by reference herein in its entirety.At step 4 the destination media agent(s) 244 b write the backup data tothe destination secondary storage device(s) 208 b. At step 5 thesynchronization is completed when the destination media agent(s) anddestination data agent(s) 242 restore the backup data to the clientcomputing device(s) 202 b. This synchronization/replication process canincorporate the techniques described in U.S. patent application Ser. No.14/721,971, entitled “Replication Using Deduplicated Secondary CopyData,” which is incorporated by reference herein in its entirety.

Where the incremental backups are applied on a frequent, on-going basis,the synchronized copies can be viewed as mirror or replication copies.Moreover, by applying the incremental backups to the destination site203 using backup data (or other secondary copy data), the productionsite 201 is not burdened with the synchronization operations. Becausethe failover site 203 can be maintained in a synchronized, “warm” state,the downtime for switching over from the production site 201 to thedestination site 203 is substantially less than with a typical restorefrom secondary storage. Thus, the production site 201 may flexibly andefficiently fail over, with minimal downtime and with relativelyup-to-date data, to a destination site 203, such as a cloud-basedfailover site. The destination site 203 can then be reverse synchronizedback to the production site 201, such as after repairs have beenimplemented or after the failure has passed.

Integrating with the Cloud Using File System Protocols

Given the ubiquity of cloud computing, it can be increasingly useful toprovide data protection and other information management services in ascalable, transparent, and highly plug-able fashion. FIG. 2B illustratesan information management system 200 having an architecture thatprovides such advantages, and incorporates use of a standard file systemprotocol between primary and secondary storage subsystems 217, 218. Asshown, the use of the network file system (NFS) protocol (or any anotherappropriate file system protocol such as that of the Common InternetFile System [CIFS]) allows the data agent 242 to be moved from theprimary storage subsystem 217 to the secondary storage subsystem 218.For instance, as indicated by the dashed line 206 around the data agent242 and the media agent 244, the data agent 242 can reside together withthe media agent 244 on the same server (e.g., a secondary storagecomputing device such as component 106), or in some other location inthe secondary storage subsystem 218.

Where NFS is used, for example, the secondary storage subsystem 218allocates an NFS network path to the client computing device 202 or toone or more target applications 210 running on the client computingdevice 202. During a backup or other secondary copy operation, theclient computing device 202 mounts the designated NFS path and writesthe data to that NFS path. The NFS path may be obtained from NFS pathdata 215 stored locally at the client computing device 202, and whichmay be a copy of or otherwise derived from NFS path data 219 stored inthe secondary storage subsystem 218.

Write requests issued by the client computing device(s) 202 are receivedby the data agent 242 in the secondary storage subsystem 218, whichtranslates the requests and works in conjunction with the media agent244 to write the data to the secondary storage device(s) 208, therebycreating a backup or other secondary copy. The storage manager 240 caninclude a pseudo-client manager 217, which can coordinate the processby, among other things, communicating information relating to the clientcomputing device 202 and application 210 (e.g., application type, clientcomputing device identifier, etc.) to the data agent 242, obtainappropriate NFS path data from the data agent 242 (e.g., NFS pathinformation) and deliver such data to the client computing device 202.

Conversely, during a restore or recovery operation the client computingdevice 202 reads from the designated NFS network path, and the readrequest is translated by the data agent 242. The data agent 242 thenworks with the media agent 244 to retrieve and forward the requesteddata to the client computing device 202 using NFS.

By moving specialized software associated with the informationmanagement system 200 such as the data agent 242 off the clientcomputing devices 202, such an architecture effectively decouples theclient computing devices 202 from the installed components of theinformation management system 200, improving both scalability andplug-ability of the information management system 200. Indeed, thesecondary storage subsystem 218 in such environments can be treatedsimply as a read/write NFS target for the primary storage subsystem 217,without the need for information management software to be installed onthe client computing device 202. As one example, an enterpriseimplementing a cloud production computing environment can add VM clientcomputing devices 202 without installing and configuring specializedinformation management software on the newly added machines. Rather,backups and restores are achieved transparently, where the new VMssimply write to and read from the designated NFS path. An example ofintegrating with the cloud using file system protocols or so-called“infinite backup” using NFS share is found in U.S. Patent ApplicationNo. 62/294,920, entitled “Improved Data Protection Operations Based onNetwork Path Information,” which is incorporated by reference in itsentirety herein. Examples of improved data restoration scenarios basedon network-path information, including using stored backups effectivelyas primary data sources, may be found in U.S. Patent Application No.62/297,057, entitled “Improved Data Restoration Operations Based onNetwork Path Information,” which is incorporated by reference in itsentirety herein.

Highly Scalable Managed Data Pool Architecture

Enterprises are seeing explosive data growth in recent years, often fromvarious applications running in geographically distributed locations.FIG. 2B shows a block diagram of an example of a highly scalable,managed data pool architecture useful in accommodating such data growth.The illustrated system 200, which may be referred to as a “web-scale”architecture according to certain embodiments, can be readilyincorporated into both open compute/storage and common-cloudarchitectures.

The illustrated system 200 includes a grid 245 of media agents 244logically organized into a control tier 231 and a secondary or storagetier 233. Media agents assigned to the storage tier 233 can beconfigured to manage a secondary storage pool 208 as a deduplicationstore, and be configured to receive client write and read requests fromthe primary storage subsystem 217, and direct those requests to thesecondary tier 233 for servicing. For instance, media agents CMA1-CMA3in the control tier 231 maintain and consult one or more deduplicationdatabases 247, which can include deduplication information (e.g., datablock hashes, data block links, file containers for deduplicated files,etc.) sufficient to read deduplicated files from the secondary storagepool 208 and write deduplicated files to the secondary storage pool 208.For instance, the system 200 can incorporate any of the deduplicationsystems and methods shown and described in greater detail in U.S. Pat.No. 9,020,900, entitled “Distributed Deduplicated Storage System,” andU.S. Pat. Pub. No. 2014/0201170, entitled “High Availability DistributedDeduplicated Storage System,” the entireties of which are herebyincorporated by reference herein.

Media agents SMA1-SMA6 assigned to the secondary tier 233 receive writeand read requests from the media agents CMA1-CMA3 in the control tier231, and access the secondary storage pool 208 to service thoserequests. The media agents CMA1-CMA3 in the control tier 231 can also beconnected to the secondary storage pool 208, and may execute read andwrite requests themselves (e.g., in response to requests from othercontrol media agents CMA1-CMA3) in addition to issuing requests to themedia agents in the secondary tier 233. Moreover, while shown asseparate from the secondary storage pool 208, the deduplicationdatabase(s) 247 can in some cases reside in storage devices in thesecondary storage pool 208.

As shown, each of the media agents 244 (e.g., CMA1-CMA3 and SMA1-SMA6)in the grid 245 can be allocated a corresponding dedicated partition251A-251I, respectively, in the secondary storage pool 208. Eachpartition 251 can include a first portion 253 containing data associatedwith (e.g., stored by) the media agent 244 corresponding to therespective partition 251. The system 200 can also implement a desiredlevel of replication, thereby providing redundancy in the event of afailure of a media agent 244 in the grid 245. Along these lines, eachpartition 251 can further include a second portion 255 storing one ormore replication copies of the data associated with one or more othermedia agents 244 in the grid.

The system 200 can also be configured to allow for seamless addition ofmedia agents 244 to the grid 245 via automatic configuration. As oneillustrative example, a storage manager (not shown) or other appropriatecomponent may determine that it is appropriate to add an additional nodeto the control tier 231, and perform some or all of the following: (i)assess the capabilities of a newly added or otherwise availablecomputing device as satisfying a minimum criteria to be configured as orhosting a media agent in the control tier 231; (ii) confirm that asufficient amount of the appropriate type of storage exists to supportan additional node in the control tier 231 (e.g., enough disk drivecapacity exists in the storage pool 208 to support an additionaldeduplication database 247); (iii) install appropriate media agentsoftware on the computing device and configure the computing deviceaccording to a predetermined template; (iv) establish a partition 251 inthe storage pool 208 dedicated to the newly established media agent 244;and (v) build any appropriate data structures (e.g., an instance of thededuplication database 247). An example of highly scalable managed datapool architecture or so-called web-scale architecture for storage anddata management is found in U.S. Patent Application No. 62/273,286entitled “Redundant and Robust Distributed Deduplication Data StorageSystem,” which is incorporated by reference in its entirety herein.

The embodiments and components thereof disclosed in FIGS. 2A and 2B, aswell as those in FIGS. 1A-1H, may be implemented in any combination andpermutation to satisfy data storage management and informationmanagement needs at one or more locations and/or data centers.

Overview of Improved Snapshot Replication Operations Based onIncremental Block Change Tracking

Many approaches to protecting data involve creating a copy of the data,such as backing up and/or replicating data stored in primary storageonto one or more secondary storage devices. One such approach is toperform data replications using snapshots. In some implementations, asnapshot capturing the state of a storage device, file system, or volumeat a specific point in time is periodically generated. For example,these snapshots may be used to provide a point-in-time image of a livestorage volume. The generated snapshots may be compared to priorsnapshots to identify changes to the primary data stored in the storagedevice. The identified changes are accessed from the primary storage andtransmitted to a replication destination.

However, depending on the implementation, snapshot replicationoperations can have a significant negative impact on the performance ofthe source or primary system. For example, computing resources of thesource system may be expended in copying data to the destination systemrather than being used to process application requests. In some cases,generating snapshots more frequently may reduce the amount of changes tothe primary data that need to be copied over for each snapshot. However,generating snapshots too frequently may have other negative consequenceson the processing and storage performance of the source system. Thus, animproved method of performing snapshot replication operations thatreduces the amount of negative performance impact on the source systemis desired.

According to some embodiments of the present disclosure, changes to theprimary data of the source system may be monitored and collected on anongoing basis between snapshots such that by the time a snapshot isgenerated, most or all of the changes to the primary data since the mostrecent snapshot replication have already been accessed from the primarystorage. In such embodiments, the amount of changes that need to beaccessed from the primary storage is significantly reduced. Thus, theamount of time and computing resources consumed by the snapshotreplication process is also reduced, thereby minimizing or reducing thenegative performance impact that the snapshot replication process mayhave on the source system.

Certain example embodiments for implementing the improved snapshotreplication process based on incremental block change tracking aredescribed below with reference to FIGS. 3-5. Although a replicationoperation is used as an example, the techniques of the presentdisclosure may be extended to backup operations or other data protection(or other information management) operations described herein.

An Exemplary System for Implementing Improved Snapshot ReplicationProcess Based on Incremental Block Change Tracking

FIG. 3 is a block diagram illustrating an exemplary system 300configured to implement an improved snapshot replication process inaccordance with one or more embodiments disclosed herein. Asillustrated, the exemplary system 300 includes a client computing device302, a storage manager 304, a media agent 306, and a secondary storagedevice 308. The client computing device 302 may generally be referred toin some cases as a primary storage subsystem 300A, and some or all ofthe storage manager 304, the media agent 306, and the secondary storagedevice 308 may sometimes be referred to as a secondary storage subsystem300B. In some embodiments, the storage manager 304 may be part of theprimary storage subsystem 300A instead of the secondary storagesubsystem 300B, or may be part of neither the primary storage subsystem300A nor the secondary storage subsystem 300B.

The client computing device 302 includes an application 310, a filterdriver 312, a primary storage device 314, and a data agent 316. Theprimary storage device 314 stores primary data 318 associated with theapplication 310 and change data 320 including some or all of the changesmade to the primary data 318 (e.g., changes since the most recentsnapshot replication or since a specific point in time). In someembodiments, the client computing device 302 may be a virtual machinerunning the application 310. Although not illustrated in FIG. 3, theclient computing device 302 may further include one or more additionalapplications and/or filter drivers. The client computing device 302 (orone or more components thereof) may further be configured to provide oneor more functions of the client computing device 102 described abovewith reference FIGS. 1A-1G.

The application 310 may be a database application, a mail application,or any other application that may be installed on the client computingdevice 302. The application 310 may generate application data (e.g.,files containing information generated or processed by the application310) and store such application data in the primary storage device 314.The application 310 may also access the data stored in the primarystorage device 314 and move, modify, or delete such data. Theapplication data stored in the primary storage device 314 may bereferred to herein as primary data (e.g., primary data 318).Alternatively, or additionally, a secondary copy of the application datamay be created by causing the application data to be transferred over anetwork connection and stored at least partially on a secondary storagedevice (e.g., secondary storage device 308), via a replication operationor another type of appropriate secondary copy operation. Such asecondary copy may be referred to herein as secondary data (e.g., firstcopy of primary data 324 and second copy of primary data 326).

The filter driver 312 may interact with the data associated with theapplication 310. For instance, the filter driver 312 may comprise a filesystem filter driver, an operating system driver, a filtering program, adata trapping program, an application, a module of the application 310,an application programming interface (“API”), or other like softwaremodule or process that, among other things, monitors and/or interceptsparticular application requests targeted at a file system, another filesystem filter driver, a network attached storage (“NAS”), a storage areanetwork (“SAN”), mass storage, and/or other memory or raw data. In someembodiments, the filter driver 312 may reside in the I/O stack of theapplication 310 and may intercept, analyze, and/or copy certain datatraveling from the application 310 to a file system.

In some embodiments, the filter driver 312 may intercept datamodification operations that include changes, updates, and newinformation (e.g., data writes) with respect to the applications ofinterest (e.g., application 310). For example, the filter driver 312 maylocate, monitor, and/or process one or more of the following withrespect to a particular application, application type, or group ofapplications: data management operations (e.g., data write operations,file attribute modifications), logs or journals (e.g., NTFS changejournal), configuration files, file settings, control files, other filesused by the application 310, combinations of the same or the like. Incertain embodiments, such data may also be gathered from files acrossmultiple storage systems within the source system (e.g., clientcomputing device 302 and/or other computing devices). Furthermore, thefilter driver 312 may be configured to monitor changes to particularfiles, such as files identified as being associated with data of theapplication 310.

In certain embodiments, the filter driver 312 may examine the operationsperformed by the application 310, determine whether the type ofoperation is one of interest for replication purposes, and/or log anychanges to the primary data 318 caused by the operations in a log file.The entries in the log file may be copies or portions of some or all ofthe data operations outputted from the application 310 to the primarystorage device 314. In some embodiments, the log entries may includeother system information, such as time stamp information or othermetadata obtained from the data.

Additionally or alternatively, the filter driver 312 may maintain achange bitmap that indicates which of the blocks associated with theprimary data 318 have been changed since the most recent replication. Insome embodiments, the data agent 316 may query the filter driver 312 for(or otherwise access) the log file and/or the change bitmap in order todetermine the blocks that are to be copied over to the replicationdestination. In some embodiments, the log file or the change bitmap mayindicate changes to the primary data 318 since the most recent query tothe filter driver 312 for the log file or change bitmap. For example,once the data agent 316 queries the filter driver 312 to retrieve thechange bitmap, the filter driver 312 may reset the change bitmap suchthat the change bitmap indicates only those changes to the primary data318 that occur after the reset. Additional examples of filter driversand data replication processes are provided in U.S. Pat. No. 7,617,262,entitled “System and Methods for Monitoring Application Data in a DataReplication System,” which is incorporated by reference herein in itsentirety. Although replication operations are used as example dataprotection operations in connection with some embodiments of the presentdisclosure, the techniques described herein may be extended to backupoperations or other data protection (or other information management)operations.

The data agent 316 comprises a module responsible for performing dataand/or storage tasks related to the client computing device 302. Forexample, the data agent 316 may manage and/or coordinate the compilationof and/or transferring of replication data from the client computingsystem 302. In other embodiments, the data agent 316 may providearchiving, migrating, and/or recovery of the primary data (e.g., primarydata 318).

In some embodiments, the data agent 316 is configured to perform datamanagement operations (e.g., snapshot replication operations) inaccordance with one or more storage policies or other preferences. Forexample, the data agent 316 may generate a snapshot of the primary dataon the client computing device 302 periodically or at specific points intime specified in a storage policy and cause the change data to betransmitted to a replication destination (e.g., secondary storage device308). The change data may include an indication of which portions (e.g.,blocks of bits or bytes on the primary storage device 314) of theprimary data have been changed since the last replication and copies ofthe modified portions or blocks.

Additionally, the data agent 316 may query the filter driver 312 toretrieve a change log or bitmap. The change log or bitmap may indicatewhich of the blocks associated with the primary data 318 have beenchanged (e.g., created, modified, deleted, etc.) since the most recentquery to the filter driver 312. Based on the change log or bitmap, thedata agent 316 may determine which blocks have been changed since thelast query to the filter driver 312 and store copies of such blocks(e.g., change data 320) in an intermediate staging area for subsequenttransmission to the destination system (e.g., secondary storage device308), for example, according to the schedule defined by the storagepolicy. In other embodiments, the copies of the changed blocks aretransmitted to the destination system after each query to the filterdriver 312 without being stored in a staging area.

Further, the data agent 316 may query the filter driver 312 and/or copythe changes to the staging area at time periods during which the clientcomputing device 302 and/or the application 310 are experiencing low (orless than average or below a threshold) activity. For example, the dataagent 316 may access historical metric data associated with the usage ofcomputing resources by the client computing device 302 and/or theapplication 310, and query the filter driver 312 and/or copy the changesto the staging area when the client computing device 302 and/or theapplication 310 are using a less than average (or below a threshold)amount of computing resources.

In some embodiments, the staging area is part of the primary storagedevice 314. In another embodiment, the staging area is implemented inanother storage device that is separate from the primary storage device314. In yet another embodiment, the staging area is implemented in astorage device whose data access requests have no or minimal impact onthe performance of the client computing device 302 and/or the primarystorage device 314. For example, the copying from such a storage deviceto the destination system may have no or minimal performance impact onthe client computing device 302 and/or the primary storage device 314.In some embodiments, the primary data 318 and the change data 320 may bestored on different virtual machines.

The data agent 316 may be configured to communicate with the media agent306 to cause copies of the primary data to be stored in the secondarystorage device 308. For example, after identifying the change data to betransmitted to the replication destination, the data agent 316 may sendthe media agent 306 a request to transmit the identified change data(e.g., from the client computing device 302 or an intermediate stagingarea) to the secondary storage device 308. Alternatively, the data agent316 may forward the identified change data to the media agent 306. Insome embodiments, the data agent 316 may communicate with the storagemanager 304 to facilitate the transmission of the identified changeddata to the appropriate media agent(s) and/or secondary storagedevice(s). The method of performing improved snapshot replicationoperations based on block change tracking according to embodiments ofthe present disclosure is further described below with reference toFIGS. 4 and 5.

Although the data agent 316 is shown in the example of FIG. 3 as beingresident on the client computing device 302 on which the application 310is running, the data agent 316 may be remotely located, physicallyand/or virtually, from the client computing device 302. In oneembodiment, the data agent 316 is running on hardware that is physicallyseparated from the client computing device 302 (or any other physicalhardware implementing the client computing device 302). In anotherembodiment, the data agent 316 is running on the same physical hardwareas the application 310 but on different virtual hardware than theapplication 310. In yet another embodiment, the data agent 316 islocated externally or remotely from the client computing device 302. Inyet another embodiment, the data agent 316 is running on a virtualmachine that is different from a virtual machine running the application310.

The data agent 316 (or one or more components thereof) may further beconfigured to provide one or more functions of the data agent 142 (orone or more components thereof) described above with reference FIGS.1A-1G.

The storage manager 304 may communicate with the data agent 316, themedia agent 306, and/or the secondary storage device 308 to facilitatethe snapshot replication operations described herein. As illustrated inFIG. 3, the storage manager 304 includes a snapshot manager 322. Thesnapshot manager 322 may manage and store data associated with thesnapshot replication operations performed on the client computing device302. For example, the snapshot manager 322 may maintain a snapshotreplication policy for each client computing system and/or application.Such a snapshot replication policy may define the schedule according towhich snapshots of the primary data 318 may be generated and theschedule according to which the change data is to be copied over to thereplication destination.

The snapshot replication policy may also specify the frequency at whichthe data agent 316 is to query the filter driver 312 and/or trackincremental block changes. In some embodiments, the frequency at whichthe filter driver 312 is to be queried for the change bitmap issubstantially higher than the frequency at which the data agent 316 (oranother component) is to generate a snapshot of the primary data andcopy over the changes that have occurred since the most recentreplication. For example, the frequency at which the filter driver 312is to be queried for the change bitmap may be every minute or every fiveminutes, whereas the frequency at which the data agent 316 (or anothercomponent) is to generate a snapshot of the primary data may be everyhour or every day. In some embodiments, the snapshot manager 322dynamically adjusts the frequency at which the filter driver 312 is tobe queried for the change bitmap and/or the frequency at which the dataagent 316 is to copy over the changes indicated in the change bitmap toa staging area or a remote location so as to reduce or minimize theimpact on the performance of the client computing device 302 and/or onthe application 310. The snapshot manager 322 may adjust one or more ofthe frequencies based on historical metric data associated with theclient computing device 302 and/or the application 310.

The storage manager 304 (or one or more components thereof) may befurther configured to provide one or more functions of the storagemanager 140 described above.

The media agent 306 may be implemented as a software module thatmanages, coordinates, and facilitates the transmission of the copies ofthe primary data (e.g., change data 320) received from the data agent316 and/or the client computing device 302 to and/or from the secondarystorage device 308 (e.g., between the client computing device 302 andthe secondary storage device 308). Although the secondary storage device308 is shown as a single secondary storage device in the example of FIG.3, it should be appreciated that any number of secondary storage devicesmay be used, as described with reference to FIG. 1D. For example, uponreceiving the data to be protected from the client computing device 302or the data agent 316, the media agent 306 may route and/or store thereceived data to the appropriate secondary storage device 308, or modifyor add to the existing copy of the data (e.g., first copy of primarydata 324, second copy of primary data 326, etc.) stored in the secondarystorage device 308.

The media agent 306 (or one or more components thereof) may further beconfigured to provide one or more functions of the media agent(s) 144(or one or more components thereof) described above with reference FIGS.1A-1G. Although not shown in FIG. 3, the media agent 306 may beimplemented on one or more corresponding secondary storage computingdevices as described above (e.g., with respect to FIG. 1C).

Although the client computing device 302 is described as the sourcesystem of the snapshot replication operations in the example of FIG. 3,in other examples, the media agent 306 and/or the secondary storagedevice 308 may operate as the source system of the snapshot replicationoperations described herein. In such an example, the data stored on thesecondary storage device 308 may be copied over to another storagedevice not illustrated in FIG. 3.

The secondary storage device 308 may store replication copies of theprimary data 318 stored in the primary storage device 314. Asillustrated, the secondary storage device 308 may store multiple copiesof the primary data 318 (e.g., first copy of primary data 324, secondcopy of primary data 326, etc.). Each copy may represent the state ofthe primary data 318 at a different point in time captured in a snapshotgenerated according to a snapshot replication policy. The secondarystorage device 308 may also store other data in addition to thosedescribed in the present disclosure.

The secondary storage device 308 (or one or more components thereof) mayfurther be configured to provide one or more functions of the secondarystorage device 108 described above with reference FIGS. 1A-1G.

The system 300 and corresponding components of FIG. 3 may further beconfigured to provide one or more functions of the system 100 andsimilarly named components shown in any of FIGS. 1A-1H, whereapplicable, such as FIG. 1D. Moreover, depending on the embodiment, thesystem 300 of FIG. 3 may additionally include any of the othercomponents shown in FIG. 1D that are not specifically shown in FIG. 3.The system 300 may include one or more of each component. All componentsof the system 300 can be in direct communication with each other orcommunicate indirectly via the client computing device 302, the storagemanager 304, the media agent 306, or the like. In certain embodiments,some of the components in FIG. 3 shown as separate components can resideon a single computing device. Alternatively, or additionally, one ormore components shown in FIG. 3 as residing on a single computing devicecan be distributed across multiple devices.

An Example Flow Diagram Illustrating Improved Snapshot ReplicationProcess

FIG. 4 is a flow diagram illustrative of one embodiment of a routine 400for performing improved snapshot replication operations based onincremental block change tracking. The routine 400 is described withrespect to the system 300 of FIG. 3. However, one or more of the stepsin the routine 400 may be implemented by other information managementsystems, such as those described in greater detail above with referenceto FIG. 1D. The routine 400 can be implemented by any one, or acombination of, a client computing device, a storage manager, a dataagent, a media agent, and the like. Although the steps in the routine400 are described as being performed by the data agent 316 of the system300, the embodiments discussed herein are not limited as such, and thesteps in the routine 400 may be performed by other components of thesystem 300, either alone or in combination.

At block 402, the data agent 316 performs a snapshot replication. Thesnapshot replication may include generating a snapshot of the primarydata 318 stored in the primary storage device 314 and transmitting anychanges to the primary data 318 since the most recent snapshotreplication performed by the data agent 316, for example, by comparingthe generated snapshot to a previously generated snapshot.

In some embodiments, generating a snapshot may cause the primary dataassociated with the generated snapshot to be read-only and cause anysubsequent changes to the primary data to be directed to an alternativelocation in the primary storage. In such embodiments, after generating asnapshot, the data agent 316 may cause the read-only copy of the primarydata (or change data) associated with the snapshot to be copied over tothe replication destination and delete the snapshot that was takenimmediately prior to the current snapshot so that the read-only copy ofthe primary data (or change data) can be consolidated.

At block 404, the data agent 316 queries the filter driver 312 toreceive a change bitmap. The filter driver 312 may maintain a changebitmap that indicates the block-level changes to the primary data 318.When queried by the data agent 316, the filter driver 312 may provide achange bitmap that indicates the block-level changes to the primary data318 since the most recent query to the filter driver 312.

At block 406, the data agent 316 updates cumulative block-level changesstored in an intermediate staging area based on the received changebitmap. In some embodiments, the cumulative block-level changes arestored in the primary storage device 314 as part of the change data 320.Alternatively, the staging area may be implemented in another storagedevice that is separate from the primary storage device 314. In anotherembodiment, the staging area may be implemented in a storage devicewhose data access requests have no or minimal impact on the performanceof the client computing device 302 and/or the primary storage device314.

In response to determining that the change bitmap indicates anadditional change to a block of data associated with a block changealready stored in the staging area, the data agent 316 may update theblock change to reflect the additional change indicated by the changebitmap (e.g., without creating a new entry or storing a new block).Alternatively, the data agent 316 may add the block changes indicated bythe change bitmap to the staging area without first determining whetherthe changes are associated with any blocks that already have blockchanges stored in the staging area. As another example, in response todetermining that the change bitmap indicates a change to a block of datathat is not stored in the staging area, the data agent 316 may store thechange associated with the block to the staging area, for example, byaccessing the block in the primary storage device 314.

At block 408, the data agent 316 determines whether a new snapshot hasbeen generated. If the data agent 316 determines that a new snapshot hasnot been generated, the routine 400 proceeds to block 404 to repeatblocks 404 through 408. Otherwise, the routine 400 proceeds to block410. In some embodiments, the data agent 316, upon determining that anew snapshot has not been generated, may further determine whether theusage of computing resources by the client computing device 302 is belowa threshold level. If the data agent 316 determines that the usage isbelow a threshold level, the routine 400 may proceed to block 404.Otherwise, the data agent 316 may wait for a predetermined time periodbefore making the determination of whether the usage is below athreshold level again or the routine 400 may proceed to block 408 again.

At block 410, the data agent 316 performs the next snapshot replication.The snapshot replication performed at block 410 may include transmittingthe changes made to the primary data 318 since the most recent snapshotreplication was performed (e.g., at block 402). For example, the dataagent 316 may determine whether the latest snapshot includes any changesto the primary data 318 that are not stored in the staging area. Thedata agent 316 may make such a determination by querying the filterdriver 312 and checking whether the change bitmap indicates anyadditional changes to the primary data 318. If the data agent 316determines that the latest snapshot generated at block 410 includeschanges not stored in the staging area, the data agent 316 causes thechanges to be transmitted to a remote destination (e.g., secondarystorage device 308) along with the changes stored in the staging area.In some embodiments, the data agent 316 may first store such additionalchanges (e.g. those associated with the latest snapshot but not yetstored in the staging area) in the staging area, and then cause all ofthe changes stored in the staging area to be transmitted to thereplication destination.

The routine 400 can include fewer, more, or different blocks than thoseillustrated in FIG. 4 without departing from the spirit and scope of thedescription. For example, although in the routine 400, the data agent316 determines at block 408 whether a next snapshot has been generated,alternatively, the data agent 316 may determine whether the filterdriver 312 is to be queried (e.g., based on a snapshot replicationpolicy). As another example, any of the operations described asperformed by the data agent 316 may be performed by the media agent 306or jointly performed by the data agent 316 and the media agent 306, andvice versa. Although the routine 400 is described herein as beingperformed by the data agent 316 on the client computing device 302, theimproved snapshot replication described herein may be performed by adata agent or another block-level backup/replication module residing onany other computing device associated with a primary storage device. Insome embodiments, the improved snapshot replication described herein mayfurther be performed by a computing system associated with the secondarystorage device 308 and/or any other secondary storage device. Moreover,it will be appreciated by those skilled in the art and others that someor all of the functions described in this disclosure may be embodied insoftware executed by one or more processors of the disclosed componentsand mobile communication devices. The software may be persistentlystored in any type of non-volatile storage.

An Illustrative Example of Improved Snapshot Replication based onIncremental Block Change Tracking

Now specific, illustrative examples will be provided with reference toFIGS. 5A and 5B. FIG. 5A illustrates an example 500A of a snapshotreplication process. FIG. 5B illustrates an example 500B of an improvedsnapshot replication process based on incremental block change tracking.

FIG. 5A shows a timeline from T0 to T1 and block changes 501-505 thathave occurred between T0 and T1. The block changes 501-505 may includesome or all of the changes made to the primary data 318 since thesnapshot replication at T0. At T1, another snapshot replication isperformed, for example, by generating a snapshot, comparing thegenerated snapshot to the snapshot generated at T0, identifying theblock changes 501-505 based on the comparison, and transmitting theblock changes 501-505 to the replication destination. Depending on thelength of the time period between T0 and T1 and/or the amount of blockchanges occurring during the time period, the replication source (e.g.,client computing device 302 of FIG. 3) may suffer significant processingdelays while the block changes 501-505 are determined and transmitted tothe replication destination.

FIG. 5B shows a timeline from T0 to T1, wherein the time period betweenT0 and T1 is further divided into sub-intervals defined by t0-t3. Theblock changes 511-515 may include some or all of the changes made to theprimary data 318 since the snapshot replication at T0. The block changes511-514 represent block changes that have already been stored in thestaging area 520 by T1, and the block change 515 represents the blockchanges that have not yet been stored in the stating area 520 by T1.

In the example of FIG. 5B, the data agent 316 may query the filterdriver 312 for the change bitmap and store any block changes in thestaging area 520 at each of t0-t3. For example, the data agent 316 mayrepeat blocks 404 and 406 of FIG. 4 at each of t0-t3. As shown in FIG.5B, the staging area 520 includes block changes 521-523. In someembodiments, the number of block changes stored in the staging area 520may be less than the total number of block changes identified based onthe change bitmap because some of the block changes may be redundant(e.g., modifying a single block more than once). Thus, by accumulatingthe block changes in the staging area 520 and copying all of the blockchanges between T0 and T1 after the snapshot is generated at T1 mayreduce the amount of change data actually transmitted to the replicationdestination system, thereby reducing the storage and/or bandwidthrequirements associated with the snapshot replication operations.

As illustrated by FIG. 5B, by tracking the block changes on an ongoingbasis between snapshots (e.g., snapshots generated at T0 and T1), theamount of changes to be accessed from the primary storage device at thetime that the snapshots are generated can be significantly reduced(e.g., from five block changes to just one in the example of FIG. 5B),thereby improving the computing and/or storage performance of the clientcomputing device.

Example Embodiments

Some example enumerated embodiments of the present invention are recitedin this section in the form of methods, systems, and/or tangiblenon-transitory computer-readable media without limitation,

EE1, A method for performing a snapshot replication operation in a datastorage system, the method comprising:

with a first computing device comprising one or more hardware processorsand in communication with a second computing device:

-   -   performing a first data protection operation at a first time        period, the first data protection operation comprising        transmitting first change data to the second computing device,        the first change data including changes to the first computing        device since a data protection operation associated with the        first computing device that immediately precedes the first time        period;    -   for each sub-interval of a plurality of sub-intervals subsequent        to the first time period,        -   querying a filter driver to receive a change bitmap, the            change bitmap including block-level changes to the first            computing device that have occurred since a most recent            query to the filter driver, and        -   based on the received change bitmap, updating cumulative            block-level changes stored in an intermediate staging area,            the cumulative block-level changes including changes to the            first computing device that occurred between the first time            period and the most recent query to the filter driver; and    -   subsequent to the plurality of sub-intervals, performing a        second data protection operation at a second time period, the        second data protection operation comprising transmitting second        change data to the second computing device, the second change        data including (i) the cumulative block-level changes stored in        the intermediate staging area and (ii) changes to the first        computing device since a query to the filter driver that        immediately precedes the second time period.

EE2, A system for performing a snapshot replication operation in a datastorage system, the system comprising:

a first computing device comprising computer hardware; and

a second computing device comprising computer hardware and in networkcommunication with the first computing device, wherein the secondcomputing device is configured to:

-   -   perform a first data protection operation at a first time        period, the first data protection operation comprising        transmitting first change data to the first computing device,        the first change data including changes to the second computing        device since a data protection operation associated with the        second computing device that immediately precedes the first time        period;    -   for each sub-interval of a plurality of sub-intervals subsequent        to the first time period,        -   query a filter driver to receive a change bitmap, the change            bitmap including block-level changes to the second computing            device that have occurred since a most recent query to the            filter driver, and        -   based on the received change bitmap, update cumulative            block-level changes stored in an intermediate staging area,            the cumulative block-level changes including changes to the            second computing device that occurred between the first time            period and the most recent query to the filter driver; and    -   subsequent to the plurality of sub-intervals, perform a second        data protection operation at a second time period, the second        data protection operation comprising transmitting second change        data to the first computing device, the second change data        including (i) the cumulative block-level changes stored in the        intermediate staging area and (ii) changes to the first        computing device since a query to the filter driver that        immediately precedes the second time period.

Terminology

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense, i.e., in the sense of “including, but notlimited to.” As used herein, the terms “connected,” “coupled,” or anyvariant thereof means any connection or coupling, either direct orindirect, between two or more elements; the coupling or connectionbetween the elements can be physical, logical, or a combination thereof.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, refer to this application as awhole and not to any particular portions of this application. Where thecontext permits, words using the singular or plural number may alsoinclude the plural or singular number respectively. The word “or” inreference to a list of two or more items, covers all of the followinginterpretations of the word: any one of the items in the list, all ofthe items in the list, and any combination of the items in the list.Likewise the term “and/or” in reference to a list of two or more items,covers all of the following interpretations of the word: any one of theitems in the list, all of the items in the list, and any combination ofthe items in the list.

In some embodiments, certain operations, acts, events, or functions ofany of the algorithms described herein can be performed in a differentsequence, can be added, merged, or left out altogether (e.g., not allare necessary for the practice of the algorithms). In certainembodiments, operations, acts, functions, or events can be performedconcurrently, e.g., through multi-threaded processing, interruptprocessing, or multiple processors or processor cores or on otherparallel architectures, rather than sequentially.

Systems and modules described herein may comprise software, firmware,hardware, or any combination(s) of software, firmware, or hardwaresuitable for the purposes described. Software and other modules mayreside and execute on servers, workstations, personal computers,computerized tablets, PDAs, and other computing devices suitable for thepurposes described herein. Software and other modules may be accessiblevia local computer memory, via a network, via a browser, or via othermeans suitable for the purposes described herein. Data structuresdescribed herein may comprise computer files, variables, programmingarrays, programming structures, or any electronic information storageschemes or methods, or any combinations thereof, suitable for thepurposes described herein. User interface elements described herein maycomprise elements from graphical user interfaces, interactive voiceresponse, command line interfaces, and other suitable interfaces.

Further, processing of the various components of the illustrated systemscan be distributed across multiple machines, networks, and othercomputing resources. Two or more components of a system can be combinedinto fewer components. Various components of the illustrated systems canbe implemented in one or more virtual machines, rather than in dedicatedcomputer hardware systems and/or computing devices. Likewise, the datarepositories shown can represent physical and/or logical data storage,including, e.g., storage area networks or other distributed storagesystems. Moreover, in some embodiments the connections between thecomponents shown represent possible paths of data flow, rather thanactual connections between hardware. While some examples of possibleconnections are shown, any of the subset of the components shown cancommunicate with any other subset of components in variousimplementations.

Embodiments are also described above with reference to flow chartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products. Each block of the flow chart illustrationsand/or block diagrams, and combinations of blocks in the flow chartillustrations and/or block diagrams, may be implemented by computerprogram instructions. Such instructions may be provided to a processorof a general purpose computer, special purpose computer,specially-equipped computer (e.g., comprising a high-performancedatabase server, a graphics subsystem, etc.) or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor(s) of the computer or other programmabledata processing apparatus, create means for implementing the actsspecified in the flow chart and/or block diagram block or blocks. Thesecomputer program instructions may also be stored in a non-transitorycomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to operate in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the acts specified in the flow chart and/or blockdiagram block or blocks. The computer program instructions may also beloaded to a computing device or other programmable data processingapparatus to cause operations to be performed on the computing device orother programmable apparatus to produce a computer implemented processsuch that the instructions which execute on the computing device orother programmable apparatus provide steps for implementing the actsspecified in the flow chart and/or block diagram block or blocks.

Any patents and applications and other references noted above, includingany that may be listed in accompanying filing papers, are incorporatedherein by reference. Aspects of the invention can be modified, ifnecessary, to employ the systems, functions, and concepts of the variousreferences described above to provide yet further implementations of theinvention. These and other changes can be made to the invention in lightof the above Detailed Description. While the above description describescertain examples of the invention, and describes the best modecontemplated, no matter how detailed the above appears in text, theinvention can be practiced in many ways. Details of the system may varyconsiderably in its specific implementation, while still beingencompassed by the invention disclosed herein. As noted above,particular terminology used when describing certain features or aspectsof the invention should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects of the invention with which that terminology isassociated. In general, the terms used in the following claims shouldnot be construed to limit the invention to the specific examplesdisclosed in the specification, unless the above Detailed Descriptionsection explicitly defines such terms. Accordingly, the actual scope ofthe invention encompasses not only the disclosed examples, but also allequivalent ways of practicing or implementing the invention under theclaims.

To reduce the number of claims, certain aspects of the invention arepresented below in certain claim forms, but the applicant contemplatesother aspects of the invention in any number of claim forms. Forexample, while only one aspect of the invention is recited as ameans-plus-function claim under 35 U.S.C sec. 112(f) (AIA), otheraspects may likewise be embodied as a means-plus-function claim, or inother forms, such as being embodied in a computer-readable medium. Anyclaims intended to be treated under 35 U.S.C. § 112(f) will begin withthe words “means for,” but use of the term “for” in any other context isnot intended to invoke treatment under 35 U.S.C. § 112(f). Accordingly,the applicant reserves the right to pursue additional claims afterfiling this application, in either this application or in a continuingapplication.

What is claimed is:
 1. A method for performing a data protection operation in a data storage system, the method comprising: transmitting, to a destination device, first snapshot data associated with a first snapshot of primary data associated with a client computing device, the first snapshot associated with a first time, wherein the client computing device is in networked communication with the destination device, and wherein the first snapshot data includes at least part of the primary data associated with the client computing device; determining a first block-level change to the primary data that occurred between the first time and a second time subsequent to the first time; updating cumulative change data stored in an intermediate staging area based at least on the first block-level change; and transmitting, to the destination device, second snapshot data associated with a second snapshot of the primary data associated with the client computing device, the second snapshot associated with a third time subsequent to the second time, wherein the second snapshot data includes (i) the cumulative change data stored in the intermediate staging area, and (ii) additional change data reflecting a second block-level change to the primary data that occurred between the second time and the third time.
 2. The method of claim 1, further comprising determining the first block-level change based at least on a first change bitmap received from a filter driver associated with the client computing device.
 3. The method of claim 2, further comprising querying the filter driver for an additional change bitmap in response to determining that the client computing device is using an amount of computing resources that is less than a threshold amount.
 4. The method of claim 2, wherein the first change bitmap indicates at least a first block in the primary data to which the first block-level change was made.
 5. The method of claim 4, wherein updating the cumulative change data comprises storing a copy of the first block indicated by the first change bitmap in the intermediate staging area.
 6. The method of claim 2, further comprising determining the second block-level change based at least on a second change bitmap received from the filter driver associated with the client computing device, wherein the second change bitmap indicates at least a second block in the primary data to which the second block-level change was made.
 7. The method of claim 1, further comprising: determining that a first block to which the first block-level change was made is stored in the intermediate staging area; and updating the first block stored in the intermediate staging area to reflect the first block-level change.
 8. The method of claim 1, wherein the intermediate staging area is remotely located from the client computing device such that copying data from the intermediate staging area to the destination device does not affect performance of the client computing device.
 9. The method of claim 1, wherein the length of time between the first time and the third time is substantially greater than the length of time between the second time and the third time.
 10. The method of claim 1, wherein the second snapshot data transmitted to the destination device includes all block change data needed to bring the primary data from the state of the primary data at the first time to the state of the primary data at the third time.
 11. A system for performing a data protection operation in a data storage system, the system comprising: a destination device comprising computer hardware; and a client computing device comprising computer hardware and in networked communication with the destination device, wherein the client computing device is configured to: transmit, to the destination device, first snapshot data associated with a first snapshot of primary data associated with the client computing device, the first snapshot associated with a first time, wherein the first snapshot data includes at least part of the primary data associated with the client computing device; determine a first block-level change to the primary data that occurred between the first time and a second time subsequent to the first time; cause cumulative change data stored in an intermediate staging area to be updated based at least on the first block-level change; and transmit, to the destination device, second snapshot data associated with a second snapshot of the primary data associated with the client computing device, the second snapshot associated with a third time subsequent to the second time, wherein the second snapshot data includes (i) the cumulative change data stored in the intermediate staging area, and (ii) additional change data reflecting a second block-level change to the primary data that occurred between the second time and the third time.
 12. The system of claim 11, wherein the client computing device is further configured to determine the first block-level change based at least on a first change bitmap received from a filter driver associated with the client computing device.
 13. The system of claim 12, wherein the client computing device is further configured to query the filter driver for an additional change bitmap in response to determining that the client computing device is using an amount of computing resources that is less than a threshold amount.
 14. The system of claim 12, wherein the first change bitmap indicates at least a first block in the primary data to which the first block-level change was made.
 15. The system of claim 14, wherein updating the cumulative change data comprises storing a copy of the first block indicated by the first change bitmap in the intermediate staging area.
 16. The system of claim 12, wherein the client computing device is further configured to determine the second block-level change based at least on a second change bitmap received from the filter driver associated with the client computing device, wherein the second change bitmap indicates at least a second block in the primary data to which the second block-level change was made.
 17. The system of claim 11, wherein the client computing device is further configured to: determine that a first block to which the first block-level change was made is stored in the intermediate staging area; and cause the first block stored in the intermediate staging area to be updated to reflect the first block-level change.
 18. The system of claim 11, wherein the intermediate staging area is remotely located from the client computing device such that copying data from the intermediate staging area to the destination device does not affect performance of the client computing device.
 19. The system of claim 11, wherein the length of time between the first time and the third time is substantially greater than the length of time between the second time and the third time.
 20. The system of claim 11, wherein the second snapshot data transmitted to the destination device includes all block change data needed to bring the primary data from the state of the primary data at the first time to the state of the primary data at the third time. 